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RULESDET NORSKE VERITAS (DNV)= STRUCTURES =Aluminium High Speed, Light CraftPART 3 - CHAPTER 1High Speed, Light CraftDesign Principles, Design LoadsandPART 3 - CHAPTER 3Hull Structural Design, Aluminium Alloy(DNV) JANUARY 2011

RULES FOR CLASSIFICATION OFHigh Speed, Light Craft andNaval Surface CraftPART 3 CHAPTER 1STRUCTURES, EQUIPMENTDesign Principles, Design LoadsJANUARY 2011This chapter has been amended since the main revision (January 2011), most recently in July 2011.See “Changes” on page 3.The content of this service document is the subject of intellectual property rights reserved by Det Norske Veritas AS (DNV). The useraccepts that it is prohibited by anyone else but DNV and/or its licensees to offer and/or perform classification, certification and/orverification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/orpursuant to this document whether free of charge or chargeable, without DNV's prior written consent. DNV is not responsible for theconsequences arising from any use of this document by others.DET NORSKE VERITAS AS

FOREWORDDET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life,property and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification andconsultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, andcarries out research in relation to these functions.The Rules lay down technical and procedural requirements related to obtaining and retaining a Class Certificate. It is usedas a contractual document and includes both requirements and acceptance criteria.The electronic pdf version of this document found through http://www.dnv.com is the officially binding version© Det Norske Veritas AS January 2011Any comments may be sent by e-mail to rules@dnv.comFor subscription orders or information about subscription terms, please use distribution@dnv.comComputer Typesetting (Adobe Frame Maker) by Det Norske VeritasIf any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation tosuch person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided thatthe maximum compensation shall never exceed USD 2 million.In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalfof Det Norske Veritas.

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 – Page 3GeneralAs of October 2010 all DNV service documents are primarily published electronically.In order to ensure a practical transition from the “print” scheme to the “electronic” scheme, all rule chapters havingincorporated amendments and corrections more recent than the date of the latest printed issue, have been given the dateJanuary 2011.An overview of DNV service documents, their update status and historical “amendments and corrections” may be foundthrough http://www.dnv.com/resources/rules_standards/.Amendments July 2011• General— The restricted use legal clause found in Pt.1 Ch.1 Sec.4 has been added also on the front page.Main changesSince the previous edition (January 2005), this chapter has been amended, most recently in July 2010. All changespreviously found in Pt.0 Ch.1 Sec.3 have been incorporated and a new date (January 2011) has been given as explainedunder “General”.In addition, the layout has been changed to one column in order to improve electronic readability.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Contents – Page 4CONTENTSSec. 1 Design Principles ................................................................................................................................ 5A. Documentation .............................................................................................................................................................. 5A 100 Plans and particulars ............................................................................................................................................. 5A 200 Information ........................................................................................................................................................... 5A 300 Strength calculations............................................................................................................................................. 5A 400 Certificates ............................................................................................................................................................ 5B. Subdivision and Arrangement ..................................................................................................................................... 6B 100 General.................................................................................................................................................................. 6B 200 Transverse watertight bulkheads........................................................................................................................... 6B 300 Position of collision bulkhead............................................................................................................................... 6B 400 Openings and closing appliances.......................................................................................................................... 6B 500 Cofferdams............................................................................................................................................................ 6B 600 Steering gear compartment ................................................................................................................................... 7C. Scantlings ....................................................................................................................................................................... 7C 100 General.................................................................................................................................................................. 7C 200 Loading conditions ............................................................................................................................................... 7C 300 Hull girder strength............................................................................................................................................... 7C 400 Resistance to slamming ........................................................................................................................................ 7C 500 Local vibrations .................................................................................................................................................... 7C 600 Miscellaneous strength requirements.................................................................................................................... 7D. Definitions ...................................................................................................................................................................... 7D 100 Symbols ................................................................................................................................................................ 7D 200 Structural terms..................................................................................................................................................... 8Sec. 2 Design Loads..................................................................................................................................... 10A. General......................................................................................................................................................................... 10A 100 Introduction......................................................................................................................................................... 10A 200 Definitions .......................................................................................................................................................... 10B. Accelerations................................................................................................................................................................ 11B 100 General................................................................................................................................................................ 11B 200 Design vertical acceleration................................................................................................................................ 12B 300 Horizontal accelerations...................................................................................................................................... 13C. Pressures and Forces .................................................................................................................................................. 14C 100 General................................................................................................................................................................ 14C 200 Slamming pressure on bottom ............................................................................................................................ 14C 300 Forebody side and bow impact pressure............................................................................................................. 16C 400 Slamming pressure on flat cross structures......................................................................................................... 17C 500 Sea pressure ........................................................................................................................................................ 18C 600 Liquids ................................................................................................................................................................ 19C 700 Dry cargo, stores and equipment ........................................................................................................................ 20C 800 Heavy units ......................................................................................................................................................... 20Sec. 3 Hull Girder Loads ............................................................................................................................ 21A. Longitudinal Bending, Shearing and Axial Loads................................................................................................... 21A 100 General................................................................................................................................................................ 21A 200 Crest landing ....................................................................................................................................................... 21A 300 Hollow landing ................................................................................................................................................... 22A 400 Hydrofoils ........................................................................................................................................................... 22A 500 Hogging and sagging bending moments............................................................................................................. 22A 600 Shear forces from longitudinal bending.............................................................................................................. 23A 700 Axial loads .......................................................................................................................................................... 23A 800 Combination of hull girder loads ........................................................................................................................ 23B. Twin Hull Loads.......................................................................................................................................................... 23B 100 General................................................................................................................................................................ 23B 200 Vertical bending moment and shear force .......................................................................................................... 24B 300 Pitch connecting moment.................................................................................................................................... 26B 400 Twin hull torsional moment................................................................................................................................ 26DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.1 – Page 5SECTION 1DESIGN PRINCIPLESA. DocumentationA 100 Plans and particulars101 The following plans shall normally be submitted for approval:— midship section including main particulars (L, B, D, T, C B Δ), maximum service speed V and design waveheight H S . (significant double amplitude)— profile and decks— shell expansion and framing including openings— watertight bulkheads and transom including openings and their closing appliances— tank structures including height of air pipes— engine room structures including tanks and foundations for heavy machinery components— afterpeak structures— forepeak structures— superstructures and deckhouses including openings with sill heights and their closing appliances— hatchways, hatch covers, ports in craft’s sides and ends including securing and tightening appliances— propeller shaft brackets with their attachment to the hull— trim flaps or foils with their attachment to the hull— rudder and rudder stock with details of bearings— arrangement and particulars of anchoring and mooring equipment with windlass— drawings of cathodic protection systems, showing anode types, mass, distribution, location and attachmentdetails (for sacrificial anodes or impressed current anodes with reference electrodes)— selection and combination of materials for exposure to sea water and/or marine atmosphere.Identical or similar structures in various positions should preferably be covered by the same plan.102 When relevant an operating manual shall be submitted, see Pt.1 Ch.1 Sec.2 A400.103 The following plans shall be submitted for information:— general arrangement— engine room arrangement— tank arrangement— capacity plan— body plan, hydrostatic curves or tables— specifications for corrosion protection, i.e. for coating, see Ch.3 Sec.2 C301 and for cathodic protectionincluding calculations, see Ch.3 Sec.2 C403.104 Additional documentation required for approval are listed in the appropriate Parts.A 200 Information201 Information which may be necessary for longitudinal strength calculations shall be submitted.202 Information which may be necessary for overall and local strength calculations shall be submitted.A 300 Strength calculations301 Strength calculations shall normally be submitted for reference demonstrating that stresses are withinrequired limits according to the rules.302 For craft of novel design and for craft with L >50 m, global hull strength analysis demonstrating stressesand deflections in the hull structure will normally be required.A 400 Certificates401 Certificates issued by Det Norske Veritas will be required for the following materials/components:— all materials to be used in hull, superstructure and deckhouses— trim foils or flaps— rudder and rudder stock— steering gear— anchor and chain/wire ropes— windlass.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.1 – Page 6B. Subdivision and ArrangementB 100 General101 The hull shall be subdivided into watertight compartments as required for the service and type notationrequested.B 200 Transverse watertight bulkheads201 At least the following transverse watertight bulkheads shall be fitted in all craft:— a collision bulkhead— a bulkhead at each end of the machinery space(s).202 The watertight bulkheads are in general to extend to the freeboard deck. Afterpeak bulkheads may,however, terminate at the first watertight deck above the waterline at draught T.203 For craft with two continuous decks and a large freeboard to the uppermost deck, the following applies:— when the draught is less than the depth to the second deck, only the collision bulkhead need extend to theuppermost continuous deck. The remaining bulkheads may terminate at the second deck— when the draught is greater than the depth to the second deck, the machinery bulkheads, with the exceptionof afterpeak bulkhead, shall extend watertight to the uppermost continuous deck.204 In craft with a raised quarter deck, the watertight bulkheads within the quarter deck region shall extendto this deck.205 For craft with the additional class notation Yacht and Patrol alternative arrangements may be acceptedbased on special considerations.B 300 Position of collision bulkhead301 The distance x c from the forward perpendicular to the collision bulkhead shall be taken between thefollowing limits:x c (minimum) = 0.05 L (m)x c (maximum) = 3.0 + 0.05 L (m)L= length in m on design waterline.302 Minor steps or recesses in the collision bulkhead may be accepted, provided the requirements tominimum and maximum distances from the forward perpendicular are complied with.303 For craft having complete or long forward superstructures, the collision bulkhead shall extend to the nextdeck above freeboard deck. The extension need not be fitted directly over the bulkhead below, provided therequirements to distances from the forward perpendicular are complied with, and the part of the freeboard deckforming the step is made watertight.For craft having particular high freeboard and long bow overhang, the position of the collision bulkhead abovethe freeboard deck may be specially considered.304 For craft with the additional class notation Yacht and Patrol alternative arrangements may be acceptedbased on special considerations.B 400 Openings and closing appliances401 Openings may be accepted in watertight bulkheads, except in that part of the collision bulkhead whichis situated below the freeboard deck.402 Openings situated below the freeboard deck shall have watertight doors with signboards fitted at eachdoor stipulating that the door be kept closed while the craft is at sea. This assumption will be stated in the“Appendix to Classification Certificate”.403 Openings in the collision bulkhead above the freeboard deck shall have weathertight doors or anequivalent arrangement. The number of openings in the bulkhead shall be reduced to the minimum compatiblewith the design and normal operation of the craft.404 For Yacht and Patrol notation alternative requirements may apply.B 500Cofferdams501 Cofferdams Fuel oil, lubricating oil and fresh water tanks shall be separated from each other bycofferdams.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.1 – Page 7B 600 Steering gear compartment601 The steering gear compartment shall be readily accessible and, as far as practicable, separated frommachinery spaces.C. ScantlingsC 100 General101 Hull scantlings are in general to be based on the two design aspects, load and strength.102 The rules have established design loads corresponding to the loads imposed by the sea and thecontainment of cargo, passengers, ballast and bunkers. The design loads are applicable in strength formulaeand calculation methods when satisfactory strength level is represented by allowable stress and/or usagefactors.103 The structure shall be capable of withstanding the static and dynamic loads which can act on the craftunder operating conditions, without such loading resulting in inadmissible deformation and loss ofwatertightness or interfering with the safe operation of the craft.104 Cyclic loads, including those from vibrations which can occur on the craft, shall not:— impair the integrity of structure during the anticipated service life of the craft— hinder normal functioning of machinery and equipment— impair the ability of the crew to carry out its duties.105 Documentation on the vibration level onboard a craft may be required.C 200 Loading conditions201 Static loads are derived from loading conditions submitted by the builder or standard conditionsprescribed in the rules.202 Wave-induced loads determined according to accepted theories, models tests or full scale measurementsmay be accepted as equivalent basis for classification. However, craft will not be classed for operation withina specific geographical area.The determination of dynamic loads shall be based on long term distribution of responses that the craft willexperience during its operating life.C 300 Hull girder strength301 For craft with length L ≤ 50 m the minimum strength standard is normally satisfied for scantlingsobtained from local strength requirements.C 400 Resistance to slamming401 Craft shall be strengthened to resist slamming. Requirements for minimum slamming loads andassociated allowable stresses are given.C 500 Local vibrations501 The evaluation of structural response to vibrations caused by impulses from engine and propeller bladesis not covered by the classification.Upon request such evaluation may be undertaken by the Society.C 600 Miscellaneous strength requirements601 Requirements for scantlings of foundations, minimum plate thicknesses and other requirements notrelating relevant load and strength parameters may reflect criteria other than those indicated by theseparameters. Such requirements may have been developed from experience or represent simplificationsconsidered appropriate by the Society.D. DefinitionsD 100 Symbols101L = length of the craft in m defined as the distance between perpendiculars. Amidships is defined as themiddle of LDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.1 – Page 8FPAPBDTΔC B= forward perpendicular is the perpendicular at the intersection of the fully loaded waterline (with thecraft at rest) with the foreside of the stem= after perpendicular is the perpendicular at the intersection of the fully loaded waterline (with the craftat rest) with the after side of sternpost or transom= greatest moulded breadth in m= moulded depth is the vertical distance in m from baseline to moulded deckline at the uppermostcontinuous deck measured amidships= fully loaded draught in m with the craft floating at rest in calm water= fully loaded displacement in tonnes in salt water (density 1.025t/m 3 ) on draught T= block coefficient, given by the formula:Δ= ------------------------------------1.025L B WL TB WL = greatest moulded breadth of the hull(s) in m at the fully loaded waterline (with the craft at rest).For multihull craft B WL is the net sum of the waterline breadthsB WL2 = greatest moulded breadth of the hull(s) in m at the fully loaded waterline (with the craft at rest)measured at L/2.For multihull craft B WL2 is the net sum of the waterline breadthsV = maximum speed in knotsg 0 = standard acceleration of gravity.= 9.81 m/s 2LCG = longitudinal centre of gravityWL = water line.D 200 Structural terms201 Freeboard deck is a deck above waterline, weathertight closed or protected, from which a freeboard ismeasured. For details see LL3 (Load Line Convention of 1966, Regulation 3).202 Superstructure is defined as a decked structure on the freeboard deck, extending from side to side of theship or with the side plating not being inboard of the shell plating more than 4% of the breadth (B). See alsoLL3.203 Strength deck is normally defined as the uppermost continuous deck. A superstructure deck which within0.4L amidships has a continuous length equal to or greater thanor3B --- +2 H (m) for monohull vessels3----- L + H (m) for twin hull vessels15shall be regarded as the strength deck instead of the covered part of the uppermost continuous deck.H = height in m between the uppermost continuous deck and the superstructure deck in question.Another deck may be defined as the strength deck after special consideration of its effectiveness.An analysis may be required to estimate the effective width of the various decks in the craft, and thereby theircontribution to the hull girder section modulus.Strength deck requirements may then have to be applied to effective party of all upper decks.204 Short superstructure deck is a superstructure deck which shall not be regarded as a strength deck.205 Weather decks are open decks or parts of decks which may be exposed to local sea and weather loads.206 Bulkhead deck (for passenger vessels and some special purpose vessels) is a deck above floodedwaterline to which the watertight bulkheads are carried.207 Weathertight is used for external surfaces above freeboard (or bulkhead) deck and means that in any seaconditions water will not penetrate into the ship.Flush with and below freeboard (or bulkhead) deck the stronger term watertight is used in the same meaning.208 Watertight elsewhere is primarily related to the internal subdivision of the ship, and means that in aflooded condition water will not penetrate from one compartment into the other.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.1 – Page 9A certain permanent set is, however, accepted in this one-accident case, which means that a watertight bulkheadis inferior to a tank bulkhead and is not accepted as such.209 Girder is a collective term for primary supporting members, usually supporting stiffeners. Other termsused are:— bottom, side and deck transverses— floor (a bottom transverse)— stringer (a horizontal girder)— web frame— vertical web.210 Stiffener is a collective term for a secondary supporting member. Other terms used are:— beam— frame— reversed frame (inner bottom transverse stiffeners)— longitudinal.211 “Flat cross structure” is a structure having an exposed, down-facing, horizontal or near-horizontalsurface above the waterline.212 Supporting structure. Strengthening of the vessel structure, e.g. a deck, in order to accommodate loadsand moments from a heavy or loaded object.213 Foundation. A device transferring loads from a heavy or loaded object to the vessel structure.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.2 – Page 10SECTION 2DESIGN LOADSA. GeneralA 100 Introduction101 Design loads given in this section are derived from full scale measurements and statistical analysis ofhigh speed and light craft designs.102 Design loads given in this section covers:— High Speed and Light Craft (HSLC) which comply with the speed requirement in Pt.1 Ch.1 Sec.2 A104and A105; i.e. V ≥ 25 knots— Light Craft (LC) according to V < 25 knots.103 New design concepts may require tank tests, theoretical studies, or full scale measurements to establishseakeeping properties and design loads.104 Design pressures caused by sea, liquid cargoes, dry cargoes, ballast and bunkers are based on extremeconditions, but are modified to equivalent values corresponding to the stress levels stipulated in the rules.105 The effects of speed reduction in heavy weather are allowed for. Limiting sea state (significant waveheight) to speed reduction may be stipulated. Such restrictions will be stated in the “Appendix to ClassificationCertificate”.106 A signboard giving the relationship between allowable speed and significant wave height as restrictedshall be posted in the wheelhouse.107 Significant wave height is the average of the 1/3 highest wave heights within the wave spectrum. Visualobservation of the “wave height” by an experienced person coincides well with the significant wave height.108 Installation of an accelerometer at LCG may be required.A 200 Definitions201 Symbols:p = design pressure in kN/m 2ρ = density of liquid or stowage rate of dry cargo in t/m 3C w = wave coefficient.For unrestricted service:C w = 0.08 L for L ≤ 100m= 6 + 0.02 L for L > 100m.Reduction of C w for restricted service is given in Table A1.Table A1 Reduction of C wClass notationR0R1R2R3R4R5-R6Reduction0010%20%40%60%Restricted service class notations are defined in Pt.1 Ch.1 Sec.2.Variation of wave coefficient C w is shown in Fig.1.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.2 – Page 11Fig. 1Wave coefficient202 The load point for which the design pressure shall be calculated is defined for various strength membersas follows:a) For plates: midpoint of horizontally stiffened plate.Half of the stiffener spacing above the lower support of vertically stiffened plate, or at lower edge of platewhen the thickness is changed within the plate.b) For stiffeners: midpoint of span.When the pressure varies other than linearly the design pressure shall be taken as the greater of:p m and p a + p---------------- b2p m’ p a and p b are calculated pressure at the midpoint and at each end respectively.c) For girders: midpoint of load area.B. AccelerationsB 100 General101 Accelerations in the craft’s vertical, transverse and longitudinal axes are in general obtained by assumingthe corresponding linear acceleration and relevant components of angular accelerations as statisticallyindependent variables. The combined acceleration in each direction may be taken as:n= number of independent variables.n2a c =a mm = 1Transverse or longitudinal component of the angular acceleration considered in the above expression shallinclude the component of gravity acting simultaneously in the same direction.102 The combined effects given in the following may deviate from the above general expression due topractical simplifications applicable to hull structural design or based on experience regarding phasing betweencertain basic components.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.2 – Page 12B 200 Design vertical acceleration201 Design vertical acceleration at craft’s centre of gravity a cg shall be specified by the builder, and isnormally not to be less than:V 3.2a cg = ------- ------------fL L 0.76 g g 0 ( m ⁄ s 2 ).Minimum a cg =1 g 0 for service restriction R0-R4Minimum a cg =0.5 g 0 for service restriction R5-------Vneed not be taken greater than 3,0Lf g= acceleration factor (fraction of g 0 ) dependent of type and service notation and service area restrictionnotation given in Table B1.Table B1 Acceleration factor f gType and serviceService area restriction notationnotationR0 R1 R2 R3 R4 R5-R6Passenger 1) 1 1 1 1 0.5Car ferry 1) 1 1 1 1 0.5Cargo 4 3 2 1 1 0.5Patrol 7 5 3 1 1 0.5Yacht 1 1 1 1 1 0.51) Service area restriction R0 is not available for class notations Passenger and Car Ferry.The design vertical acceleration is an extreme value with a 1% probability of being exceeded, in the worstintended condition of operation.202 Unless otherwise established, the design acceleration at different positions along the craft’s length shallnot be less than:a v = k v a cgk v= longitudinal distribution factor taken from Fig.2.203 The allowable speed corresponding to the design vertical acceleration a cg , may be estimated from theformulas for the relationship between instantaneous values of a cg , V and H s , given in 204 and 205.204 When V ⁄ L ≥ 3:H sβ cg= significant wave height in m= deadrise angle at LCG in degrees= minimum 10°= maximum 30°B WL2 = water line breadth at L/2 in m.For twin- and multi hull vessels the total breadth of the hulls (exclusive tunnels) shall be usedg 0 = standard acceleration of gravity = 9.81 m/s 2k h = hull type factor given in Table B2.Table B2 Hull type factorHull typek hMonohull, Catamaran 1.0Wave Piercer 0.9SES, ACV 0.8Foil assisted hull (see 206) 0.7SWATH (see 206) 0.7k h g 0 Ha cg----------- S= -------------- + 0.084 ( 50 – β1650 B WL2 cg ) V------- 2 LB 2WL2------------------------ ( m ⁄ s 2 ) LΔDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.2 – Page 13The hull type factor k h is an estimate for correction of the vertical acceleration depending on the different typesof hull forms.205 When V ⁄ L < 3:a cg=6 H S------ V0.85 + 0.35------- g0 ( m ⁄ s 2 )L L206 Unless other values are justified by calculations according to accepted theories, model tests or full scalemeasurements, the speed reductions implied by 204 and 205 shall be applied. For SWATH and craft with foilassisted hull, accelerations shall normally be determined in accordance with the above direct methods.207 Relationships between allowable speed and significant wave height will be stated in the “Appendix toClassification Certificate”.2.4k v2.00.41.61.20.8AP 0.2L 0.4L 0.6L 0.8L FPMidshipFig. 2Longitudinal distribution factor for vertical design accelerationB 300 Horizontal accelerations301 The craft shall be designed for a longitudinal (surge) acceleration not less thana l=2.5 C W------- 0.85 + 0.25-------V 2 gL L0-------Vneed not be taken greater than 4LTentative formula for the relation between instantaneous values of a l , H S and V:a l ( 1.67) H S= ------ 0.85 + 0.35-------V 2 gL L0a l is intended for calculation of forward directed inertia forces and may have to be increased based on theoverall impact possibilities in craft’s front.a l may be simultaneous with downward vertical inertia in forebody.302 It may be necessary to pay attention to transverse acceleration from forced roll in bow seas.Period of forced roll to be taken:LT R = ---------------------------------------1.05 + 0.175-------V ( s)LDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.2 – Page 14V------- need not be taken greater than 4LMaximum roll inclination:Resulting transverse acceleration:a tθ r=π h--------- w(radians)2L= 2-------π 2 θ T R r r r ( m ⁄ s 2 )Static component g 0 sin θ r to be added, when above axis of roll.h w = maximum wave height in which 70% of maximum service speed will be maintained, minimum 0.6 C wr r = height above axis of roll.Axis of roll to be taken— at waterline for twin hull craft— at D/2 for monohull craft.C. Pressures and ForcesC 100 General101 The external and internal pressures and forces considered to influence the scantlings of stiffened panelsare:— static and dynamic sea pressures— static and dynamic pressures from liquids in a tank— static and dynamic loads from dry cargoes, stores and equipment.102 The design sea pressures are assumed to be acting on the craft’s outer panels at full draught.103 The internal pressures are given for the panel in question irrespectively of possible simultaneous pressurefrom the opposite side.104 The bottom structure, forebody side/bow structure and flat cross structures shall be strengthened to resistthe effects of slamming and impact.105 The gravity and acceleration forces from heavy units of cargo and equipment may influence thescantlings of primary strength members.C 200 Slamming pressure on bottom201 The design slamming pressure on bottom of craft with speed V ⁄ L ≥ 3 shall be taken as:k l = longitudinal distribution factor from Fig. 3n = number of hulls, 1 for monohulls, 2 for catamarans. Trimarans and other multihulls will be speciallyconsidered.A = design load area for element considered in m 2 .For plating A shall not be taken greater than 2.5 s 2 .For stiffener and girder A is taken as the product:spacing x spanA need not for any structure be taken less than 0.002 Δ T --T OP sl 1.3k Δl------ 0.3 0.7T 50 – β x=nAO------------------- a50 – β cg ( kN ⁄ m 2 )cg= draught at L/2 in m at normal operation condition at service speedΔ = fully loaded displacement in tonnes in salt water on draught Tβ x = deadrise angle in degrees at transverse section considered (minimum 10°, maximum30 °)β cg = deadrise angle in degrees at LCG (minimum 10°, maximum 30°)a cg = design vertical acceleration at LCG from B200 (a V calculated at LCG).DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.2 – Page 15For transverse sections with no pronounced deadrise angle, β cg and β x may be estimated according to Fig.4.The bottom slamming pressure need not be applied to craft with no significant hydrodynamic or air cushion liftin normal operating condition; i.e. SWATH hull forms.202 Bottom slamming pressure shall be applied on elements within the area extending from the keel line tochine, upper turn of bilge or pronounced sprayrail.Fig. 3Longitudinal slamming pressure distribution factor for high speed mode slammingFig. 4Deadrise angle for round bottom section203 All craft shall be designed for a pitching slamming pressure on bottom as given below:P ------------------k 21sl tan( β x )k C 120T L= – ------------ ( kN ⁄ m 2 )a b W L ß x as in 201k ak bT L= 1 for plating= 1.1 – 20 l A /L; maximum 1.0, minimum 0.35 for stiffeners and girdersl A = longitudinal extent in m of load area= 1 for plating and longitudinal stiffeners and girders=L/40l + 0.5 (maximum 1.0) for transverse stiffeners and girders (l = span in m of stiffener or girder)= lowest service speed draft in m at FP measured vertically from waterline to keel line or extended keelline.Above pressure shall extend within a length from FP:0.1 + 0.15-------V LLV ⁄ Lneed not to be taken greater than 3. p sl may be gradually reduced to zero at 0.175 L aft of the abovelength.Pitching slamming pressure shall be exposed on elements within the area extending from the keel line to chine,upper turn of bilge or pronounced sprayrail.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.2 – Page 16204 Pressure on bottom structure shall not be less than given in 500.C 300 Forebody side and bow impact pressure301 Forebody side and bow impact pressure shall be taken as, in kN/m 2 :V ⁄ L need not be taken greater than 3.A = design load area for element considered in m 2For plating A shall not be taken greater than = 2.5 s 2 (m 2 )For stiffeners and girders A need not be taken smaller than e 2 (m 2 )In general A need not be taken smaller than L B wl /1000 (m 2 )e = vertical extent of load area, measured along shell perpendicular to the waterlinex = distance in m from AP to position considered= correction factor for length of craftC L250L – L 2= ------------------------, L not be taken greater than 100m15000C H = correction factor for height above waterline to load point0.5= 1 – ------- h 0C W may be reduced according to A201h 0 = vertical distance in m from the waterline at draught T to the load pointα = flare angle taken as the angle between the side plating and a horizontal line, measured at the pointconsidered. See Fig.5γ = angle between the waterline and a longitudinal line measured at the point considered. See Fig.6= acceleration parameter:a 0C W0.7 LC L C HP sl = -------------------------- A 0.3 0.6 0.4------- V + sin γ cos( 90° – α)+L2.1 a-------------- 00.4------- V + 0.6 sin 90° – αC B L( ) x L -- – 0.4 2 a 0=3 C W V------- + CL V-------LC V=L------- , maximum 0.250αFig. 5Flare angle αCDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.2 – Page 17Fig. 6Waterline angle γ302 Forebody side and bow pressure shall not be taken less than according to 500.303 The impact pressure according to 301 is be calculated for longitudinal positions between 0.4 L and bow.304 In vertical direction the impact pressure shall extend from bottom chine or upper turn of bilge to maindeck or vertical part of craft side.Upper turn of bilge shall be taken at a position where deadrise angle reaches 70°, but not higher than thewaterline.If no pronounced bottom chine or upper turn of bilge is given (V-shape), the impact pressure shall extend fromkeel to main deck or vertical part of craft side.C 400 Slamming pressure on flat cross structures401 The design slamming pressure on flat cross structures (catamaran tunnel top, etc.), shall be taken as:P sl 2.6 k Δt--- 0.3 H C=a Acg 1 – ------ ( kN ⁄ m 2 ) H LA = design load area for element considered. See 201H C = minimum vertical distance in m from WL to load point in operating conditionk t = longitudinal pressure distribution factor according to Fig.7H L = necessary vertical clearance in m from WL to load point to avoid slamming= 0.22 L 0.8k c – ----------- L 1000 k c = hull type clearance factor0.3 for catamaran, wave piercer0.3 for SES, ACV0.3 for hydrofoil, foilcatamaran0.5 for SWATH.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.2 – Page 181.5k tSWATH1.00.5CATAMARANWAVE PIERCERSESACVHYDROFOILFOILCATAP 0.5L FPFig. 7Flat cross structure slamming distribution factor k t402 Slamming pressure shall not be less than the sea pressure according to 500 (side above WL).C 500 Sea pressure501 Pressure acting on the craft’s bottom, side (including superstructure side) and weather decks shall betaken as:— for load point below design waterline:— for load point above design waterline:Minimum sea pressures are given in Table C1.Table C1 Minimum sea pressuresNotationSidesWeatherdecksR0, R1, R2, R3 6.5 5 3R4 5 4 3R5-R6 4 3 3h 0k sp 10h 0 k s 1.5 h 0= + – ---- CW ( kN ⁄ m 2 ) T p = a k s ( C W – 0.67 h 0 ) ( kN ⁄ m 2 )Roofs higher than 0.1 Labove WL= vertical distance in m from the waterline at draught T to the load point= 7.5 aft of amidships=5/C B forward of FP.Between specified areas k s shall be varied linearly, see Fig.8a = 1.0 for craft’s sides and open freeboard deck= 0.8 for weather decks above freeboard deckC W = wave coefficient according to A200.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.2 – Page 19Fig. 8Sea load distribution factor502 The design pressure on superstructure end bulkheads and deckhouses shall not be taken less than:P min = 5 + (5 + 0.05 L) sin α (kN/m 2 )for lowest tier of unprotected frontP min =5 (kN/m 2 ) for aft end bulkheadsP min = 5 + 0.025 L sin α (kN/m 2 ) elsewherewhere α is the angle between the bulkhead/side and deck.h o , C W and k s as given in 501.a= 2.0 for lowest tier of unprotected fronts= 1.5 for deckhouse fronts= 1.0 for deckhouse sides= 0.8 elsewhere.503 The design pressure on watertight bulkheads (compartment flooded) shall be taken as:p = 10 h b (kN/ 2 )h bp = a k s ( C W – 0.67 h 0 ) ( kN ⁄ m 2 )= vertical distance in m from the load point to the top of bulkhead or to flooded waterline, if deeper.504 The design pressure on deck or inner bottom forming part of watertight bulkhead shall not be less thanfor the bulkhead at same level.C 600 Liquids601 Tanks for bunkers and tank bulkheads shall normally be designed for liquids of density equal to that ofsea water, taken as ρ = 1.025 t/m 3 (i.e. ρ g 0 ≅ 10).602 The pressure in tanks shall be taken as the greater of:p = ρ (g 0 + 0.5 a v ) h s (kN/m 2 )p = 0.67 ρ g 0 h p (kN/m 2 )DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.2 – Page 20p = ρ g 0 h s + 10 (kN/m 2 ) for L ≤ 50mp = ρ g 0 h s + 0.3 L – 5 (kN/m 2 ) for L > 50ma v = as given in B200h s = vertical distance in m from the load point to the top of tankh p = vertical distance in m from the load point to the top of air pipe or filling station.For tanks which may be filled to top of air pipe or filling station and subsequently subjected to accelerations,the pressure shall be modified accordingly.603 The design pressure on wash bulkheads is given by:p = 3.5 l t (kN/m 2 )l t = the greater distance in m to the next bulkhead forward or aft.For wash bulkhead plating, requirement to thicknesses may have to be based on the reaction forces imposed onthe bulkhead by boundary structures.C 700 Dry cargo, stores and equipment701 The pressure on inner bottom, decks or hatch covers shall be taken as:p = ρ H (g 0 + 0.5 a v ) (kN/m 2 )a v = as given in B200H = stowage height in m.Standard values of ρ and H are given in Table C2.If decks (excluding inner bottom) or hatch covers are designed for cargo loads heavier than the standard loadsgiven in Table C2, the notation dk (+) or ha (+), respectively, will be entered in the Register of Ships. Thedesign cargo load in t/m 2 will be given for each individual cargo space in the “Appendix to ClassificationCertificate”.702 When the weather deck or weather deck hatch covers are designed to carry deck cargo, the pressure is ingeneral to be taken as the greater of p according to 500 and 700.703 For transverse bulkheads in way of general cargo holds, the design loads given for watertight bulkheadsapply.Table C2 Standard load parametersDecksWeather deck and weather deck hatchcovers intended for cargoSheltered deck, sheltered hatch coversand inner bottom for cargo or storesParametersρ H = 1.0 t/m 2ρ = 0.7 t/m 3Platform deck in machinery space ρ H = 1.6 t/m 2Accommodation decksH = vertical distance in m from the load point to the deck above. For loadpoints below hatchways H shall be measured to the top of coamingρ H = 0.35 t/m 2 , when not directly calculated, including the deck's own mass.Minimum 0.25 t/m 2 .C 800 Heavy units801 Heavy units The vertical force acting on supporting structures from rigid units of cargo, equipment orother structural components shall normally be taken as:P v = (g 0 + 0.5 a v ) M (kN)M = mass of unit in tonnesa v = as given in B200.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.3 – Page 21SECTION 3HULL GIRDER LOADSA. Longitudinal Bending, Shearing and Axial LoadsA 100 General101 For craft of ordinary hull form with L/D less than 12 and with length less than 50 m, the minimumstrength standard is normally satisfied for scantlings obtained from local strength requirements.102 For other types of craft, craft with L/D greater than 12 and for craft with length greater than 50 m, thelongitudinal strength shall be calculated as described in the following.A 200 Crest landing201 For craft with V ⁄ L ≥ 3 a slamming pressure is acting on an area equal to the reference area, A R ,given below. The area shall be situated with the load point at LCG of the craft. The weight distribution of thehull girder shall be increased by the acceleration at LCG. The hull girder shall be considered out of water.1 0.2 a cg+ ------ g 0A R = k Δ ------------------------------ ( m 2 )Twhere:k = 0.7 for crest landing= 0.6 for hollow landing.202 The load combination which is illustrated in Fig.1 may be required analysed with actual weightdistribution along the hull beam.203 The longitudinal midship bending moment may be assumed to be:M B=Δl-- ( g2 0 + a cg ) se w – -- ( kNm) 4Δa cge wl s= displacement in tonnes= vertical design acceleration at LCG= one half of the distance from LCG of the fore half body to the LCG of the aft half body of the vessel, in m= 0.25 L if not known (0.2 L for hollow landing)= longitudinal extension of slamming reference area:A Rl s = ------b swhere b s is the breadth of the slamming reference area. See Fig.2.(e w - l s /4) shall not be taken less than 0.04 L.204 The reduction of M B towards ends will be determined by the weight distribution and the extent of A R .Fig. 1Crest landingFig. 2Breadth of midship slamming reference areaDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.3 – Page 22Fig. 3Hollow landingA 300 Hollow landing301 Hollow landing is similar to crest landing except that the reference area A R is situated towards AP andFP as shown in Fig.3.302 The load combination may be required analysed with actual weight distribution along the hull beam.303 The longitudinal midship bending moment may be assumed to be:ΔM B = -- ( g2 0 + a cg ) ( e r – e w )e r = mean distance from the centre of the A R /2 end areas to the vessels LCG in m.(e r – e w ) not to be taken less than 0.04 LA 400 Hydrofoils401 The calculation of longitudinal strength of hydrofoils shall be effected for the most severe condition. Asa rule this will be considering the craft sustained above the water surface by the foils and supposing it to bestationary in the navigation condition, taking into account vertical acceleration as well as the verticalcomponents of the hydrodynamic action of the water on the foils.A 500 Hogging and sagging bending moments501 For all craft an investigation of hogging and sagging bending moments taking into account anyimmersed/ emerged structures may be required.502 The investigation is in its simplest form to be based on a predicted phasing between pitch/heave and thepassage of a meeting design wave, and shall include the pitch angle and the inertia forces to be expected in thehogging and sagging conditions.503 Tentative formulae for bending moments (still water + wave) for high speed light craft:For monohull craft (in kNm):M tot hog = M sw + 0.19 C W L 2 B C BM tot sag = M sw + 0.14 C W L 2 B (C B + 0.7)M sw = still water moment in the most unfavourable loading condition in kNm 1)=0.11 C w L 2 B C B (kNm) in hogging if not known= 0 in sagging if not known. 2)For twin hull craft (in kNm):M tot hog = M sw + 0.19 C W L 2 (B WL2 + k 2 B tn ) C BM tot sag = M sw + 0.14 C W L 2 (B WL2 + k 3 B tn ) (C B + 0.7)M sw = still water moment in the most unfavourable loading condition in kNm 1)= 0.5 Δ L (kNm) in hogging if not known= 0 in sagging if not known. 2) .Additional correction of 20% to be added to the wave sagging moment for craft with large flare in the foreship.1) Documentation of the most unfavourable still water conditions shall normally be submitted for information.2) If the still water moment is a hogging moment, 50% of this moment can be deducted where the design sagging moment M totsag iscalculated.B tn = breadth in m of cross structures (tunnel breadth)k 2 and k 3 = empirical factors for the effect of cross structure immersion in hogging and sagging waves. If noother value available:DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.3 – Page 23z – 0.5 Tk 2 = 1 – --------------------------------, minimum 00.5 T + 2 C Wz – 0.5 Tk 3 = 1 – -------------------------------------, minimum 00.5 T + 2.5 C Wk 4z= 0.25 in general, when V is maximum speed of craft,= 0.35 when V is taken as the slowed down speed= height in m from base line to wet deck (top of tunnel).A 600 Shear forces from longitudinal bending601 A vertical hull girder shear force may be related to the hull girder bending moments from 200, 300, and500 as follows:Q b=M---------------- B(kN)0.25 LM B = bending moment in kNm.A 700 Axial loads701 Axial loads from— surge = Δ al— thrust and— sea end pressuresmay have to be estimated and added together in most exposed areas (forebody buckling control).al= maximum surge acceleration, not to be taken less than:0.4 g 0 for ------- V ≥ 5L( 0.2) g 0 for------- V ≤ 3Lwith linear interpolation for intermediate V ⁄ L.A 800 Combination of hull girder loads801 The hull girder loads vertical bending, vertical shear and torsion (B400) shall be considered accordingto the following combinations:— 80% longitudinal bending and shear + 60% torsion— 60%% longitudinal bending and shear + 80% torsion.802 The hull girder loads transverse vertical bending moment (B200) and pitch connecting moment (B300)shall be considered according to the following combinations:— 70% transverse bending + 100% pitch connecting— 100% transverse bending + 70% pitch connecting.B. Twin Hull LoadsB 100 General101 The transverse strength of twin hull connecting structure may be analysed for moments and forcesspecified below.102 Design forces and moments given in 200, 300 and 400 shall be used unless other values are verified bymodel tests or full scale measurements or if similar structures have proved to be satisfactory in service.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.3 – Page 24B 200 Vertical bending moment and shear force201 For craft with ( V ⁄ L ≥ 3)and L < 50 m, the twin hull transverse bending moment may be assumed to be:M S =Δ a cg b---------------- (kNm)sb = transverse distance between the centrelines of the two hullss = factor given in Table B1.Fig. 4Transverse vertical bending moment and shear force202 For craft with L ≥ 50 m the twin hull transverse bending moment shall be assumed to be the greater of:a cgM S = M S0 1 + ------ (kNm) g 0M S = M S0 + F y ( z – 0.5T) (kNm)M S0F y= still water transverse bending moment in kNm= horizontal split force on immersed hull=⋅3.25 1 + 0.0172-------V 1.05 1.30 L T ( 0.5 BWL ) 0.146LL BMAX L1 ------------------ BMAX B------------------ ---------------MAX 2.10– +HL L B WL 1 (kN)H 1 = 0.143Bmin H S,MAXB WL = maximum width (m) in water line (sum of both hulls)B MAX = maximum width (m) of submerged part (sum of both hulls)L BMAX = length in metres where B MAX /B WL > 1H S,MAX = maximum significant wave height in which the vessel is allowed to operate (m)B = beam over all (m)z = height from base line to neutral axis of cross structure (m).V-------Lneed not be taken greater than 3See Fig.5 for explanation of symbols. The expression should not be used for Surface Effect Ships (SES) incushion borne mode, but shall be applied to SES in a survival condition with cushion air pressure equal to zero.A reduction factor of 0.8 is then to be applied to the dynamic split moment.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.1 Sec.3 – Page 250.5B WL=0.5B MAX0.5B WL0.5B WL0.5B MAX0.5B MAXL B MAXFig. 5Definition of parameters in case of different sectional shapes203 The vertical shear force in centreline between twin hull may be assumed to be:S=Δ a------------- cg(kN)qq = factor given in Table B1.Table B1 Factors s and qService restriction s qR4-R6R3R2R1R08.07.56.55.54.06.05.55.04.03.0204 For craft with length L ≥ 50 m the twin hull still water transverse bending moment shall be assumed to be:M S0 = 4.91 Δ ( y b – 0.4 B 0.88 ) (kNm)M S0 = still water transverse bending momentD = displacement in tonnesy b = distance in m from centre line to local centre line of one hull (see Fig.6 for definition)B = width over all in m.y bFig. 6Definition of local geometry for one hull on twin hull craftDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.1 Sec.3 – Page 26The expression shall not be used for Surface Effect Ships (SES) or for twin hulls with significant weight alongthe centre line.B 300 Pitch connecting moment301 The twin hull pitch connection moment (see Fig.7) may be assumed to be:M P=Δ a cg L----------------- (kNm)8Fig. 7Pitch connecting moment and torsion moment on twin hull connectionB 400 Twin hull torsional moment401 Hull torsional moment of twin hull may be assumed to be:b = distance in m between the two hull centerlines.Δ a cg bM t = ---------------- (kNm)4DET NORSKE VERITAS AS

RULES FOR CLASSIFICATION OFHigh Speed, Light Craft and NavalSurface CraftPART 3 CHAPTER 3STRUCTURES, EQUIPMENTHull Structural Design,Aluminium AlloyJANUARY 2011This chapter has been amended since the main revision (January), most recently in July 2011.See “Changes” on page 3.The content of this service document is the subject of intellectual property rights reserved by Det Norske Veritas AS (DNV). The useraccepts that it is prohibited by anyone else but DNV and/or its licensees to offer and/or perform classification, certification and/orverification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/orpursuant to this document whether free of charge or chargeable, without DNV's prior written consent. DNV is not responsible for theconsequences arising from any use of this document by others.DET NORSKE VERITAS AS

FOREWORDDET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life,property and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification andconsultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, andcarries out research in relation to these functions.The Rules lay down technical and procedural requirements related to obtaining and retaining a Class Certificate. It is usedas a contractual document and includes both requirements and acceptance criteria.The electronic pdf version of this document found through http://www.dnv.com is the officially binding version© Det Norske Veritas AS January 2011Any comments may be sent by e-mail to rules@dnv.comFor subscription orders or information about subscription terms, please use distribution@dnv.comComputer Typesetting (Adobe Frame Maker) by Det Norske VeritasIf any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation tosuch person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided thatthe maximum compensation shall never exceed USD 2 million.In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalfof Det Norske Veritas.

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Changes – Page 3CHANGESGeneralAs of October 2010 all DNV service documents are primarily published electronically.In order to ensure a practical transition from the “print” scheme to the “electronic” scheme, all rule chapters havingincorporated amendments and corrections more recent than the date of the latest printed issue, have been given the dateJanuary 2011.An overview of DNV service documents, their update status and historical “amendments and corrections” may be foundthrough http://www.dnv.com/resources/rules_standards/.Amendments July 2011• General— The restricted use legal clause found in Pt.1 Ch.1 Sec.4 has been added also on the front page.Main changesSince the previous edition (July 2000), this chapter has been amended, most recently in January 2006. All changespreviously found in Pt.0 Ch.1 Sec.3 have been incorporated and a new date (January 2011) has been given as explainedunder “General”.In addition, the layout has been changed to one column in order to improve electronic readability.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Contents – Page 4CONTENTSSec. 1 Structural Principles .......................................................................................................................... 8A. General........................................................................................................................................................................... 8A 100 The scantling reduction......................................................................................................................................... 8A 200 Aluminium alloys ................................................................................................................................................. 8B. Bottom Structures ......................................................................................................................................................... 8B 100 Longitudinal stiffeners.......................................................................................................................................... 8B 200 Web frames ........................................................................................................................................................... 8B 300 Longitudinal girders.............................................................................................................................................. 8B 400 Engine girders ....................................................................................................................................................... 8B 500 Double bottom, if fitted ........................................................................................................................................ 9C. Side Structure................................................................................................................................................................ 9C 100 Stiffeners............................................................................................................................................................... 9D. Deck Structure............................................................................................................................................................... 9D 100 Longitudinal stiffeners.......................................................................................................................................... 9D 200 Bulwarks ............................................................................................................................................................... 9E. Flat Cross Structure...................................................................................................................................................... 9E 100 Definition .............................................................................................................................................................. 9E 200 Longitudinal stiffeners.......................................................................................................................................... 9F. Bulkhead Structures ................................................................................................................................................... 10F 100 Transverse bulkheads.......................................................................................................................................... 10F 200 Corrugated bulkheads ......................................................................................................................................... 10G. Superstructures and Deckhouses............................................................................................................................... 10G 100 Definitions .......................................................................................................................................................... 10G 200 Structural continuity ........................................................................................................................................... 10H. Structural Design in General ..................................................................................................................................... 11H 100 Craft arrangement ............................................................................................................................................... 11H 200 Soft local transitions ........................................................................................................................................... 11H 300 Impact strength ................................................................................................................................................... 11I. Some Common Local Design Rules........................................................................................................................... 11I 100 Definition of span ............................................................................................................................................... 11I 200 Effective girder flange ........................................................................................................................................ 12I 300 Sniped stiffeners ................................................................................................................................................. 13J. Support of Equipment and Outfitting Details.......................................................................................................... 13J 100 Heavy equipment, appendages etc...................................................................................................................... 13J 200 Minor outfitting details ....................................................................................................................................... 13K. Structural Aspects not Covered by Rules ................................................................................................................. 13K 100 Deflections .......................................................................................................................................................... 13K 200 Local vibrations .................................................................................................................................................. 14Sec. 2 Materials and Material Protection ................................................................................................. 15A. General......................................................................................................................................................................... 15A 100 Application.......................................................................................................................................................... 15A 200 Material certificates ............................................................................................................................................ 15B. Structural Aluminium Alloy ...................................................................................................................................... 15B 100 General................................................................................................................................................................ 15B 200 Aluminium grades............................................................................................................................................... 15B 300 Chemical composition ........................................................................................................................................ 15B 400 Mechanical properties......................................................................................................................................... 15C. Corrosion Protection................................................................................................................................................... 17C 100 General................................................................................................................................................................ 17C 200 For information and approval ............................................................................................................................. 17C 300 Coating................................................................................................................................................................ 17C 400 Cathodic protection............................................................................................................................................. 18C 500 Other materials in contact with aluminium......................................................................................................... 19D. Other Materials ........................................................................................................................................................... 19D 100 Steel .................................................................................................................................................................... 19D 200 Connections between steel and aluminium......................................................................................................... 19DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Contents – Page 5D 300 Fibre Reinforced Plastic (FRP)........................................................................................................................... 19Sec. 3 Manufacturing.................................................................................................................................. 20A. General......................................................................................................................................................................... 20A 100 Basic requirements.............................................................................................................................................. 20B. Inspection..................................................................................................................................................................... 20B 100 General................................................................................................................................................................ 20B 200 Penetrant testing.................................................................................................................................................. 20B 300 Radiographic testing ........................................................................................................................................... 20B 400 Ultrasonic examination ....................................................................................................................................... 20C. Extent of Examination ................................................................................................................................................ 20C 100 General................................................................................................................................................................ 20D. Acceptance Criteria for NDT..................................................................................................................................... 20D 100 Acceptance criteria.............................................................................................................................................. 20E. Testing .......................................................................................................................................................................... 21E 100 Tanks................................................................................................................................................................... 21E 200 Closing appliances .............................................................................................................................................. 21Sec. 4 Hull Girder Strength........................................................................................................................ 22A. General......................................................................................................................................................................... 22A 100 Introduction......................................................................................................................................................... 22A 200 Definitions .......................................................................................................................................................... 22B. Vertical Bending Strength.......................................................................................................................................... 22B 100 Hull section modulus requirement...................................................................................................................... 22B 200 Effective section modulus................................................................................................................................... 22B 300 Hydrofoil on foils................................................................................................................................................ 23B 400 Longitudinal structural continuity ...................................................................................................................... 23B 500 Openings ............................................................................................................................................................. 23C. Shear Strength............................................................................................................................................................. 24C 100 Cases to be investigated...................................................................................................................................... 24D. Cases to be Investigated.............................................................................................................................................. 24D 100 Inertia induced loads........................................................................................................................................... 24E. Transverse Strength of Twin Hull Craft................................................................................................................... 24E 100 Transverse strength ............................................................................................................................................. 24E 200 Allowable stresses .............................................................................................................................................. 25Sec. 5 Plating and Stiffeners....................................................................................................................... 26A. General......................................................................................................................................................................... 26A 100 Introduction......................................................................................................................................................... 26A 200 Definitions .......................................................................................................................................................... 26A 300 Allowable stresses............................................................................................................................................... 26B. Plating .......................................................................................................................................................................... 26B 100 Minimum thicknesses ......................................................................................................................................... 26B 200 Bending............................................................................................................................................................... 27B 300 Slamming ............................................................................................................................................................ 27C. Stiffeners ...................................................................................................................................................................... 28C 100 Bending............................................................................................................................................................... 28C 200 Slamming ............................................................................................................................................................ 29Sec. 6 Web Frames and Girder Systems ................................................................................................... 30A. General......................................................................................................................................................................... 30A 100 Introduction......................................................................................................................................................... 30A 200 Definitions .......................................................................................................................................................... 30A 300 Minimum thicknesses ......................................................................................................................................... 30A 400 Allowable stresses............................................................................................................................................... 31A 500 Continuity of strength members ......................................................................................................................... 31B. Web Frames and Girders ........................................................................................................................................... 31B 100 General................................................................................................................................................................ 31B 200 Effective flange................................................................................................................................................... 31B 300 Effective web ...................................................................................................................................................... 32B 400 Strength requirements ......................................................................................................................................... 32DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Contents – Page 6B 500 Girder tripping brackets ...................................................................................................................................... 33B 600 Girder web stiffeners........................................................................................................................................... 34Sec. 7 Pillars and Pillar Bulkheads............................................................................................................ 35A. General......................................................................................................................................................................... 35A 100 Introduction......................................................................................................................................................... 35A 200 Definitions .......................................................................................................................................................... 35B. Pillars............................................................................................................................................................................ 35B 100 Arrangement of pillars ........................................................................................................................................ 35B 200 Cross-section particulars..................................................................................................................................... 35B 300 Pillar scantlings................................................................................................................................................... 35B 400 Pillars in tanks..................................................................................................................................................... 36C. Supporting Bulkheads ................................................................................................................................................ 37C 100 General................................................................................................................................................................ 37Sec. 8 Weld Connections............................................................................................................................. 38A. General......................................................................................................................................................................... 38A 100 Introduction......................................................................................................................................................... 38A 200 Welding particulars............................................................................................................................................. 38B. Types of Welded Joints............................................................................................................................................... 38B 100 Butt joints............................................................................................................................................................ 38B 200 Tee or cross joints ............................................................................................................................................... 38C. Size of Connections ..................................................................................................................................................... 39C 100 Fillet welds, general............................................................................................................................................ 39C 200 Fillet welds and penetration welds subject to high tensile stresses .................................................................... 39C 300 End connections of girders, pillars and cross ties............................................................................................... 40C 400 End connections of stiffeners.............................................................................................................................. 40Sec. 9 Direct Strength Calculations ........................................................................................................... 43A. General......................................................................................................................................................................... 43A 100 Introduction......................................................................................................................................................... 43A 200 Application.......................................................................................................................................................... 43B. Plating .......................................................................................................................................................................... 43B 100 General................................................................................................................................................................ 43B 200 Calculation procedure ......................................................................................................................................... 43B 300 Allowable stresses............................................................................................................................................... 43C. Stiffeners ...................................................................................................................................................................... 43C 100 General................................................................................................................................................................ 43C 200 Calculation procedure ......................................................................................................................................... 44C 300 Loads................................................................................................................................................................... 44C 400 Allowable stresses............................................................................................................................................... 44D. Girders ......................................................................................................................................................................... 44D 100 General................................................................................................................................................................ 44D 200 Calculation methods ........................................................................................................................................... 44D 300 Design load conditions........................................................................................................................................ 44D 400 Allowable stresses............................................................................................................................................... 45Sec. 10 Buckling Control .............................................................................................................................. 46A. General......................................................................................................................................................................... 46A 100 Definitions .......................................................................................................................................................... 46B. Longitudinal Buckling Load ...................................................................................................................................... 47B 100 Longitudinal stresses........................................................................................................................................... 47C. Transverse Buckling Load ......................................................................................................................................... 47C 100 Transverse stresses.............................................................................................................................................. 47D. Plating .......................................................................................................................................................................... 47D 100 Plate panel in uni-axial compression .................................................................................................................. 47D 200 Plate panel in shear ............................................................................................................................................. 49D 300 Plate panel in bi-axial compression and shear .................................................................................................... 49E. Stiffeners in Direction of Compression ..................................................................................................................... 50E 100 Lateral buckling mode ........................................................................................................................................ 50E 200 Torsional buckling mode .................................................................................................................................... 51DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Contents – Page 7E 300 Web and flange buckling .................................................................................................................................... 52F. Stiffeners Perpendicular to Direction of Compression............................................................................................ 52F 100 Moment of inertia of stiffeners ........................................................................................................................... 52G. Elastic Buckling of Stiffened Panels .......................................................................................................................... 53G 100 Elastic buckling as a design basis ....................................................................................................................... 53G 200 Allowable compression....................................................................................................................................... 53H. Girders ......................................................................................................................................................................... 54H 100 Axial load buckling............................................................................................................................................. 54H 200 Girders perpendicular to direction of compression............................................................................................. 54H 300 Buckling of effective flange................................................................................................................................ 54H 400 Shear buckling of web ........................................................................................................................................ 55DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.1 – Page 8SECTION 1STRUCTURAL PRINCIPLESA. GeneralA 100 The scantling reduction101 The scantling reductions for high speed and light craft structures compared with Rules for Classificationof Ships are based on:—a certain stiffener spacing reduction ratio ---s s rs = chosen spacing in ms r = basic spacing = -------------------------- 2100 ( + L)m in general1000— longitudinal framing in bottom and strength deck— extended longitudinal and local buckling control— a sea and weather service restriction.A 200 Aluminium alloys201 The alloy grades are listed in Sec.2 Tables B1 to B4.202 The various formulae and expressions involving the factor f 1 may be applied when:σ ff 1 = --------240σ f = yield stress is not to be taken greater than 70% of the ultimate tensile strength.The material factor f 1 included in the various formulae and expressions is given in Sec.2 Tables B1 to B3 forthe un-welded condition and in Table B4 for the welded condition.B. Bottom StructuresB 100 Longitudinal stiffeners101 Single bottoms as well as double bottoms are normally to be longitudinally stiffened.102 The longitudinals should preferably be continuous through transverse members. If they are to be cut attransverse members, i.e. watertight bulkheads, continuous brackets connecting the ends of the longitudinals areto be fitted or welds are to be dimensioned accordingly.103 Longitudinal stiffeners are to be supported by bulkheads and web frames.104 Longitudinal stiffeners in slamming areas should have a shear connection to transverse members.B 200 Web frames201 Web frames are to be continuous around the cross section i.e. floors side webs and deck beams are to beconnected. Intermediate floors may be used.202 In the engine room plate floors are to be fitted at every frame. In way of thrust bearings additionalstrengthening is to be provided.B 300 Longitudinal girders301 Web plates of longitudinal girders are to be continuous in way of transverse bulkheads.302 A centre girder is normally to be fitted for docking purposes.303 Manholes or other openings should not be positioned at ends of girders without due consideration beingtaken of shear loadings.B 400 Engine girders401 Under the main engine, girders extending from the bottom to the top plate of the engine seating are to befitted.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.1 – Page 9402 Engine holdingdown bolts are to be arranged as near as practicable to floors and longitudinal girders.403 In way of thrust bearing and below pillars additional strengthening is to be provided.B 500 Double bottom, if fitted501 Manholes are to be cut in the inner bottom, floors and longitudinal girders to provide access to all partsof the double bottom. The vertical extension of lightening holes is not to exceed one half of the girder height.The edges of the manholes are to be smooth. Manholes in the inner bottom plating are to have reinforcementrings. Manholes are not to be cut in the floors or girders in way of pillars.502 In double bottoms with transverse stiffening, longitudinal girders are to be stiffened at every transverseframe.503 The longitudinal girders are to be satisfactorily stiffened against buckling.C. Side StructureC 100 Stiffeners101 The craft's sides may be longitudinally or vertically stiffened.Guidance note:It is advised that longitudinal stiffeners are used near bottom and strength deck.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---102 The continuity of the longitudinals is to be as required for bottom and deck longitudinals respectively.D. Deck StructureD 100 Longitudinal stiffeners101 Decks are normally to be longitudinally stiffened.102 The longitudinals should preferably be continuous through transverse members. If they are to be cut attransverse members, i.e. watertight bulkheads, continuous brackets connecting the ends of the longitudinals areto be fitted.103 The plate thickness is to be such that the necessary transverse buckling strength is achieved, or transversebuckling stiffeners may have to be fitted intercostally.D 200 Bulwarks201 The thickness of bulwark plates is not to be less than required for side plating in a superstructure in thesame position.202 A strong bulb section or similar is to be continuously welded to the upper edge of the bulwark. Bulwarkstays are to be in line with transverse beams or local transverse stiffening. The stays are to have sufficient widthat deck level. The deck beam is to be continuously welded to the deck in way of the stay. Bulwarks on forecastledecks are to have stays fitted at every frame.Stays of increased strength are to be fitted at ends of bulwark openings. Openings in bulwarks should not besituated near the ends of superstructures.203 Where bulwarks on exposed decks form wells, ample provision is to be made to freeing the decks forwater.E. Flat Cross StructureE 100 Definition101 Flat cross structure is horizontal structure above waterline like bridge connecting structure between twinhulls, etc.E 200 Longitudinal stiffeners201 Flat cross structures are normally to be longitudinally stiffened.202 The longitudinals should preferably be continuous through transverse members. If they are to be cut attransverse members, i.e. watertight bulkheads, continuous brackets connecting the ends of the longitudinals areDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.1 – Page 10to be fitted or welds are to be dimensioned accordingly.203 Longitudinal stiffeners are to be supported by bulkheads and web frames.F. Bulkhead StructuresF 100 Transverse bulkheads101 Number and location of transverse watertight bulkheads are to be in accordance with the requirementsgiven in Ch.1 Sec.1 B200.102 The stiffening of the upper part of a plane transverse bulkhead is to be such that the necessary transversebuckling strength is achieved.F 200 Corrugated bulkheads201 Longitudinal and transverse bulkheads may be corrugated.202 For corrugated bulkheads the following definition of spacing applies (see Fig. 1):s= s 1 for section modulus calculations=1.05 s 2 or 1.05 s 3 for plate thickness calculations.Fig. 1Corrugated bulkheadG. Superstructures and DeckhousesG 100 Definitions101 Superstructure is defined as a decked structure on the freeboard deck, extending from side to side of theship or with the side plating not inboard of the shell plating more than 4% of the breadth (B).102 Deckhouse is defined as a decked structure above the strength deck with the side plating being inboardof the shell plating more than 4% of the breadth (B).Long deckhouse - deckhouse having more than 0.2 L of its length within 0.4 L amidships.Short deckhouse - deckhouse not defined as a long deckhouse.G 200 Structural continuity201 In superstructures and deckhouses, the front bulkhead is to be in line with a transverse bulkhead in thehull below or be supported by a combination of girders and pillars. The after end bulkhead is also to beeffectively supported. As far as practicable, exposed sides and internal longitudinal and transverse bulkheadsare to be located above girders and frames in the hull structure and are to be in line in the various tiers ofaccommodation. Where such structural arrangement in line is not possible, there is to be other effective support.202 Sufficient transverse strength is to be provided by means of transverse bulkheads or girder structures.203 At the break of superstructures, which have no set-in from the ship's side, the side plating is to extendbeyond the ends of the superstructure, and is to be gradually reduced in height down to the deck or bulwark.The transition is to be smooth and without local discontinuities. A substantial stiffener is to be fitted at the upperedge of plating. The plating is also to be additionally stiffened.204 In long deckhouses, openings in the sides are to have well rounded corners. Horizontal stiffeners are tobe fitted at the upper and lower edge of large openings for windows.Openings for doors in the sides are to be substantially stiffened along the edges. The connection area betweendeckhouse corners and deck plating is to be increased locally.Deck girders are to be fitted below long deckhouses in line with deckhouse sides.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.1 – Page 11205 Deck beams under front and aft ends of deckhouses are not to be scalloped for a distance of 0.5 m fromeach side of the deckhouse corners.206 For deckhouse side stiffeners the scantlings need not be greater than required for tween deck frames withequivalent end connections.207 Casings supporting one or more decks above are to be adequately strengthened.H. Structural Design in GeneralH 100 Craft arrangement101 Attention is drawn to the importance of structural continuity in general.102 The craft arrangement is to take into account:— continuity of longitudinal strength, including horizontal shear area to carry a strength deck along— transverse bulkheads or strongwebs— web or pillar rings in engine room— twin hull connections— access for inspection— superstructures and deckhouses:— direct support— transitions— deck equipment support— multi-deck pillars in line, as practicable— external attachments, inboard connections.103 Structural details in spaces that will be coated are to be designed in such way that a sound layer of coatingcan be achieved everywhere.H 200 Soft local transitions201 Gradual taper or soft transition is specially important in high speed aluminium vessels, to avoid:— stress corrosion and fatigue in heavy stressed members— impact fatigue in impact loaded members.202 End brackets, tripping brackets etc. are not to terminate on unsupported plating.Brackets are to extend to the nearest stiffener, or local plating reinforcement is to be provided at the toe of thebracket.H 300 Impact strength301 The slamming pressure in Ch.1 is (contrary to the Rules for Classification of Ships) expressed as anequivalent static load, and is to be compared with ordinary allowable stresses.I. Some Common Local Design RulesI 100 Definition of span101 The effective span of a stiffener (l) or girder (S) depends on the design of the end connections in relationto adjacent structures. Unless otherwise stated the span points at each end of the member, between which thespan is measured, is to be determined as shown on Fig.1. It is assumed that brackets are effectively supportedby the adjacent structure. For stiffeners, see also Fig. 2 or Sec.5.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.1 – Page 12lRSb23 b23 RlSlb23 bSTIFFENERSGIRDERSFig. 2Span pointsI 200 Effective girder flange201 For girders with curved face plate, e.g. web frames, the effective area of the flange is given by:A e = k t f b f (mm 2 )b f= total face plate breadth in mmk = flange efficiency coefficient, see also Fig. 3rt= k 1--------- fb= 1.0 maximumk 1 =------------------------------------------------------------------------------0.643( sinhβcoshβ+ sinβcosβ)sinh 2 β + sin2 βfor symmetrical and unsymmetrical free flange=0.78--------------------------------------------------------------------------------------( sinhβ+ sinβ) ( coshβ– cosβ)sinh 2 β + sin2 βfor girder flange with two webs=β =1.56( coshβ– cosβ)-------------------------------------------------sinhβ+ sinβfor box girder flange with multiple webs1.285b---------------- (rad)rt fb= 0.5 (b f – t w ) for symmetrical free flangesDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.1 – Page 13st ft wr=b f for unsymmetrical free flanges=s – t w for box girder flanges= spacing of supporting webs for box girder (nun)= face plate thickness in general (mm)=t w (maximum) for unsymmetrical free flanges= web plate thickness (mm)= radius of curved face plate (mm)Fig. 3Effective width of curved face plates for alternative boundary conditions202 The effective width of curved plate flanges, or effective width of plate at knuckles, is to be speciallyconsidered.I 300 Sniped stiffeners301 Stiffeners with sniped ends may be allowed where dynamic loads are small and vibrations considered tobe of small importance.J. Support of Equipment and Outfitting DetailsJ 100 Heavy equipment, appendages etc.101 Whether the unit to be supported is covered by classification or not, the forces and moments at points ofattachment have to be estimated and followed through hull reinforcements in line, through craft girder andpillar system (taking into account hull stresses already existing) until forces are safely carried to craft's side orbulkheads.102 Doublers should be avoided normal to a tensile force.J 200 Minor outfitting details201 Generally connections of outfitting details to the hull are to be such that stress-concentrations areminimized and welding to high stressed parts are avoided wherever possible.Connections are to be designed with smooth transitions and proper alignment with the hull structure elements.Terminations are to be supported.202 Connections to topflange of girders and stiffeners are to be avoided if not well smoothened. Preferablysupporting of outfittings are to be welded to the stiffener web.K. Structural Aspects not Covered by RulesK 100 Deflections101 Requirements for minimum moment of inertia or maximum deflection under load are limited to structurein way of hatches and doors and some other special cases.102 Deflection problems in general are left to designer's consideration.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.1 – Page 14K 200 Local vibrations201 The evaluation of structural response to vibrations caused by impulses from engine and propeller bladesand jet units are not covered by the classification, but the builder is to provide relevant documentation.Guidance note:HSC Code 3.4:Cyclic loads, including those from vibrations which can occur on the craft should not:a) impair the integrity of structure during the anticipated service life of the craft or the service life agreedwith the Administration;b) hinder normal functioning of machinery and equipment; andc) impair the ability of the crew to carry out its duties.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---Upon request such evaluation may be undertaken by the Society.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.2 – Page 15SECTION 2MATERIALS AND MATERIAL PROTECTIONA. GeneralA 100 Application101 The rules in this chapter apply to wrought aluminium alloys for objects classified or intended forclassification with the Society.A 200 Material certificates201 Rolled and extruded wrought aluminium alloys, glass reinforced plastic and core materials for hullstructures and rolled steel are normally to be supplied with DNV material certificates.202 For class certificate requirement for chemical composition, mechanical properties, heat treatment andrepair of defects, see Pt.2 Ch.2.203 Particular attention is to be given to aluminium hull materials specification in Pt.2 Ch.2.204 Requirements for material certificates for forgings, castings and other materials for special parts andequipment are stated in connection with the rule requirements for each individual part.B. Structural Aluminium AlloyB 100 General101 Aluminium alloy for marine use may be applied in hulls, superstructures, deckhouses, hatch covers andsundry items.B 200 Aluminium grades201 Aluminium alloys are to have a satisfactory resistance to corrosion in marine environments. Grades forwelded structures are to be weldable, applying one of the welding methods approved by the Society.202 For major hull structural components, alloys with temper H116/H321 for rolled products, and alloys withtemper T5/T6 for extruded products, are normally to be used. The use of 0- or F temper must be agreed withthe Society.203 The use of 6000 series aluminium alloys in direct contact with sea water may be restricted depending onapplication and corrosion protection system. The use of these alloys are to be agreed with the Society.204 In weld zones (HAZ) of rolled or extruded products, the factor f 1 given in Table B4 may in general beused as basis for the scantling requirements.205 Welding consumables are to be chosen according to Table C2 in Pt.2 Ch.3 Sec.2. The consumable chosenare to have minimum mechanical properties not less than specified for the parent alloy in the welded condition.B 300 Chemical composition301 The chemical composition is to satisfy the requirements in Pt.2 Ch.2. Other alloys or alloys which do notfully comply with Pt.2 Ch.2, may be accepted by the Society after consideration in each particular case. Specialtests and/or other relevant information, e.g. which confirm a satisfactory corrosion resistance and weldability,may be required.B 400 Mechanical properties401 Requirements to mechanical properties for different delivery conditions are given in Tables B1 and B2for wrought products, extruded products and rivet bars/-rivets, respectively. Other delivery conditions withrelated mechanical properties may be accepted by the Society after consideration in each particular case.Table B1 Factor f 1 for wrought aluminium alloy sheets, strips and plates, t: 2 mm ≤ t ≤ 40 mmDNV Designation Temper f 1NV-5052H32H340.610.69NV-5154A 0, H111 0.35NV-5754 H24 0.69NV-5454H32H340.730.79DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.2 – Page 16Table B1 Factor f 1 for wrought aluminium alloy sheets, strips and plates, t: 2 mm ≤ t ≤ 40 mm (Continued)DNV Designation Temper f 1V-5086 H116, H32H340.800.88NV-5083 H116, H321 0.89NV-5383 H116, H34 0.89Note: For tempers 0 and H111, the factor f 1 is to be taken from Table B4.Table B2 Factor f 1 for extruded aluminium alloy profiles, rods and tubes, t: 2 mm ≤ t ≤ 25 mmDNVTemperDesignationf 1NV-6060 T5 0.55NV-6061T4T5/T60.460.76NV-6063T5T60.440.60NV-6005A T5/T6 0.76NV-6082T4T5/T60.460.90Note: Table B2 only applies when the main loading direction is logitudinal to the extrusion, see also Table B3.Table B3 Factor f 1 for extruded aluminium alloy profiles, rods and tubes, t: 2 mm ≤ t ≤ 25 mm, transverse toextruding directionDNVDesignationTemper f 1NV-6060 T5 0.51NV-6061T4T5/T60.460.71NV-6005AT5/T66 < t < 1010 < t < 250.760.67NV-6082 T5 / T6 0.85Note: Table B2 only applies when the main loading direction is logitudinal to the extrusionTable B4 Factor f 1 in the welded conditionDNVTemper FillerDesignationf 1NV-5052 0, H111, H32, H34 5356 0.27NV-5154A 0, H111 5356-5183 0.35NV 5754 0, H111, H24 5356-5183 0.33NV 5454 0, H111, H32, H34 5356-5183 0.35NV-5086 0, H111, H116, H32, H34 5356-5183 0.42NV-5083H116, H321H116, H321535651830.53 1)0.60 1)NV-5383 H116, H34 5183 0.64 2)NV-6060 T5 5356-5183 0.27NV-6061T4T5/T65356-5183 0.480.48NV-6063T55356-5183 0.27T6NV-6005A T5/T6 5356-5183 0.48NV-6082T4T5/T65356-5183 0.460.481) The utilisation of the material is higher than given by the f 1 factor as given in Sec. 1 A. This is due to extendedutilisation in Rules for HS, LC and NSC, f 1 =(σ 1 /240) x 1.102) The utilisation of the material is higher than given by the f 1 factor as given in Sec. 1 A. This is due to extendedutilisation in Rules for HS, LC and NSC, f 1 =(σ 1 /240) x 1.10DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.2 – Page 17C. Corrosion ProtectionC 100 General101 Loss of structural strength due to corrosion is not acceptable.102 All surfaces that are not recognised as inherently resistant to the actual marine environment are to beadequately protected against corrosion.Guidance note:In these rules, corrosion is defined as degradation of material due to environmental influence.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---C 200 For information and approval201 Specifications for corrosion protection, i.e. for coating, if applied, see 301, and for cathodic protection(including calculations), see 403, are to be submitted for information. The specifications are basis for approvalof drawings of the cathodic protection system.202 Drawings of cathodic protection system, e.g. fastening, numbers and distribution of anodes and referenceelectrodes (if impressed current), are subject to approval.203 Selection and combination of materials for exposure to sea water and/or marine atmosphere are subjectto approval.C 300 Coating301 If coating is applied, the specification is to be submitted for information.Guidance note:Coating of aluminium hulls is normally not required (see B200). However, hulls normally need to be coated for antifoulingpurposes. When coating is applied, it will influence the corrosion resistance of the hull, and constitute a basisfor cathodic protection design. The coating system including surface preparation before coating should therefore besubmitted for information.The following is normally included in a specification for coating:— metal surface cleaning and preparation before application of the primer coat, including treatment of edges andwelds— build-up and application of coating system with individual coats— curing times and over-coating intervals— acceptable temperatures of air and metal surface and dryness or humidity conditions during the above mentionedoperations (normally, the metal surface is minimum 3 °C above the dew point and the relative humidity is below85%)— thickness of individual coats and final coating system— resistance to cathodic disbonding (for coatings to be used in connection with impressed current).---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---302 A sound anti-corrosion coating should always be combined with the anti-fouling coating on the externalhull.303 Anti-corrosion coating is not to contain copper or other constituents that may cause galvanic corrosionon the aluminium hull.304 Hull integrated water ballast tanks and other tanks holding corrosive liquids are to be coated. Allstiffeners and frames in these tanks are to be welded to plating with double continuous welding, see Sec.8 B202.305 In other internal compartments of the hull where corrosive water is likely to occur, the lower 0.5 m ofthe internal bottom surface, measured along the plate on each side of the keel, and the corresponding sectionof the bulkheads, is normally to be coated. The preparation of surfaces including welds and edges shall be suchthat the coating can be properly applied.Guidance note:The use of 6000 alloys containing more than 0.15% Cu in internal compartments without coating may be restricted.Stagnant, chloride-containing water in internal compartments, e.g. condensation water, may cause corrosion onaluminium alloy plates and structures. Corrosion attacks will usually be of localised type, e.g. in the form of pitting.Corrosion attacks of galvanic type may also occur, see also 500, e.g. if equipment made of other metal alloy remainsin electrical contact with aluminium alloy material.Corrosion attacks of the above mentioned types can be reduced by means of e.g.:— coating applied as described above— regular cleaning, drying and inspection of the actual compartment— electrical isolation of any other metallic part from aluminium alloy plates and structures— use of dehumidifying equipment in a closed compartmentDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.2 – Page 18— ventilation holes (minimum 2)— drainage holes— hot air fans.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---C 400 Cathodic protection401 Cathodic protection of aluminium hulls can be obtained with aluminium or zinc sacrificial anodes orimpressed current. Magnesium based sacrificial anodes are not to be used, and impressed current is not to beused in internal hull compartments.402 Cathodic protection is normally to be applied to aluminium hull craft due to electrical connection of thealuminium with another metals (in propeller, water jet, etc.), which may initiate galvanic corrosion, and toprotect the hull against local corrosion and damage that normally will occur in protective coatings.403 The following is normally to be included in a cathodic protection specification:— areas to be protected (m 2 ) for hull and attached metallic components such as water jet unit and water jet duct— stipulated protective current density demand (mA/m 2 ) for coated and not coated surfaces of hull andattached components, respectively— total current demand (A)— target design life of cathodic protection system— anode material and manufacturer— for sacrificial anodes; calculation of anode mass, distribution, total number— for impressed current systems; current capacity of rectifiers and anodes— for impressed current systems; reference electrodes, system control and monitoring arrangement, cablingand procedures for exchange or renewal of components— target protective potential difference to be obtained— drawings of cathodic protection systems, showing anode types, mass, distribution, location and attachmentdetails (for sacrificial anodes or impressed current anodes with reference electrodes)— cathodic protection system drawings shall be in compliance with the specification and calculations for thesame.Guidance note:The current density demand will vary dependent upon the speed of hull, the speed of propeller, and the type of metallicmaterial to be protected (aluminium, stainless steel, etc.).The target protective potential difference for aluminium alloy surfaces may be minus 950 mV versus the Ag/AgCl/seawater reference electrode, with an acceptable potential difference range of minus 800 mV to minus 1150 mV, i.e.approximately as for carbon steel and stainless steel. Due concern must be given to the possibility of detrimentaloverprotection of aluminium.Stainless steel surfaces in water jet units of high speed craft may need a current density of up to about 300 mA/m 2 tobe protected, while values as high as 500 mA/m 2 may give overprotection problems.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---404 For documentation of instrumentation and automation, including computer based control andmonitoring, see Pt.4 Ch.9 Sec.1.405 The designed (target) service life of a cathodic protection system is normally to be at least as long as theexpected time interval between dockings.406 With impressed current cathodic protection systems, precautions are to be taken to avoid:1) overprotection or excessive negative potential differences locally, especially on aluminium surfaces(implying transpassive corrosion) as well as2) loss of protection,by means of anode screens, automatic voltage control, overprotection alarm, or similar. The protective potentialdifference is to be kept within a specified and agreed range, see Guidance note to 403.407 Direct voltage stray currents may impose rapid electrolytic corrosion damage to hulls and is to beavoided.Guidance note:Stray D.C. sources may be shore connections (e.g. ramps, cranes, cables, etc.), not properly grounded weldingmachines, etc. Special precautions should be taken if welding is carried out with the craft afloat, or if the craft isconnected to electrical power in port.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.2 – Page 19C 500 Other materials in contact with aluminium501 If other metallic materials are used in propellers or impellers, piping, pumps, valves, etc. and are incontact with the aluminium hull, provisions are to be made to avoid galvanic corrosion. Acceptable provisionsare either one of or a combination of:— coating of water or moisture exposed surfaces— electrical isolation of different materials from each other— cathodic protection.Guidance note:Full electrical isolation of e.g. propeller or impeller from hull is usually difficult. Contact will be established when thepropeller is idle.Wooden material, cloth, debris, non-adherent coating or other organic material remaining in durable contact withaluminium may cause under-deposit corrosion on aluminium due to local oxygen deficiency at the surface.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---D. Other MaterialsD 100 Steel101 Structural steel may be used in sundry items such as rudders, foils, propeller shaft brackets, etc.102 For requirements for chemical composition, mechanical properties, heat treatment, testing and repair ofdefects, see Pt.2.103 The material factor f 1 = 1 for ordinary ship quality steel.104 All steel surfaces are to be protected against corrosion by paint of suitable composition or other effectivecoating.105 Shop primers applied over areas which will subsequently be welded, are to be of a quality accepted bythe Society as having no detrimental effect on the finished weld.See “Register of Approved Manufacturers” and “Register of Type Approved Products”.106 Coating systems are to be suitable for use on any previously applied shop primer.The coating and the assumed application conditions must have been approved by the Society. Such approvalwill normally be given as a «Type approval».The shipbuilders are to present a written declaration stating that the coating has been applied as specified.Guidance note:Upon request approval programs for coating systems may be obtained from the Society.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---D 200 Connections between steel and aluminium201 If there is risk of galvanic corrosion, provisions are to be made, see C500.202 Aluminium plating connected to a steel boundary bar is wherever possible to be arranged on the sideexposed to moisture.203 Direct contact between exposed wooden materials, e.g. deck planking, and aluminium is to be avoided.204 Bolts with nuts and washers are either to be of stainless steel or hot galvanized steel. The bolts are ingeneral to be fitted with sleeves of insulating material.D 300 Fibre Reinforced Plastic (FRP)301 FRP materials, core materials and fillers are to be approved according to Sec. 3.302 Other reinforcement and plastic materials may be approved on the basis of relevant documentation andtesting in each individual case.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.3 – Page 20SECTION 3MANUFACTURINGA. GeneralA 100 Basic requirements101 Welding of hull structures, machinery installations and equipment are to be carried out by approvedwelders, with approved welding consumables and at welding shops recognised by the Society. See Sec.2.102 Shot blasting, priming and coating are to be carried out under indoor conditions. For coatingspecification and documentation, see Sec.2.103 For vessels longer than 50 m, a plan for non-destructive testing (NDT) is to be submitted for approval.B. InspectionB 100 General101 Welds are to be subject to visual survey and inspection as fabrication proceed. NDT is to be performedaccording to established procedures and if required, qualified for the work.102 All examinations are to be carried out by competent personnel. The NDT operators are to be qualifiedaccording to a recognised certification scheme accepted by the Society. The certificate is clearly to state thequalifications as to which examination method and within which category the operator is qualified.B 200 Penetrant testing201 Penetrant testing is to be carried out as specified in the approved procedures.B 300 Radiographic testing301 Radiographic testing is to be carried out as specified in the approved procedures.302 Processing and storage are to be such that the films maintain their quality throughout the agreed storagetime. The radiographs are to be free from imperfections due to development processing.B 400 Ultrasonic examination401 Ultrasonic testing is to be carried out as specified in the approved procedures. Ultrasonic examinationprocedures are to contain sketches for each type of joint and dimensional range of joints which clearly showscanning pattern and probes to be used.402 The examination record is to include the imperfection position, the echo height, the dimensions (length),the depth below the surface and, if possible, the defect type.C. Extent of ExaminationC 100 General101 All welds are to be subject to visual examination. In addition to the visual examination, at least 2 to 5%of total welded length are to be examined by penetrant examination and/or radiographic examination. Forhighly stressed areas the extent of examination may be increased.102 If defects are detected, the extent of examination is to be increased to the surveyor’s satisfaction.D 100Acceptance criteriaD. Acceptance Criteria for NDT101 All welds are to show evidence of good workmanship. The quality is normally to comply with ISO 10042quality level C, intermediate. For highly stressed areas more stringent requirements, such as ISO level B, maybe applied.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.3 – Page 21E. TestingE 100 Tanks101 Protective coating systems may be applied before water testing.All pipe connections to tanks are to be fitted before testing. If engine bed plates are bolted directly on the innerbottom plating, the testing of the double bottom tank is to be carried out with the engine installed.102 Unless otherwise agreed, all tanks are to be tested with a water head equal to the maximum pressure towhich the compartment may be exposed. The water is in no case to be less than to the top of the air pipe or toa level h 0 above the top of the tank except where partial filling alone is prescribed.h 0 = 0.03 L - 0.5 (m), minimum 1, generally= pressure valve opening pressure when exceeding the general value.E 200 Closing appliances201 Inner and outer doors below the waterline are to be hydraulically tested.202 Weathertight and watertight closing appliances not subjected to pressure testing are to be hose tested.The nozzle inside diameter is to be 12.5 mm and the pressure at least 250 kN/m 2 . The nozzle should be held ata distance of maximum 1.5 m from the item during the test.Alternative methods of tightness testing may be considered.203 All weathertight or watertight doors and hatches are to be function tested.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.4 – Page 22SECTION 4HULL GIRDER STRENGTHA. GeneralA 100 Introduction101 In this section requirements for longitudinal and transverse hull girder strength is given. In addition,buckling control according to Sec. 10 may be required.102 Longitudinal strength has generally to be checked for the craft types and sizes mentioned in theintroduction to Ch.1 Sec.3.103 For new designs (prototypes) of large and structurally complicated craft (e.g. multi-hull types) acomplete 3-dimensional global analysis of the transverse strength, in combination with longitudinal stresses, isto be carried out.104 Buckling strength in bottom and deck may, however, have to be checked also for the other craft.A 200 Definitions201 Moulded deck line, Rounded sheer strake, Sheer strake and Stringer plate are as defined in Fig.1.Fig. 1Deck cornersB 100101Hull section modulus requirementB. Vertical Bending StrengthZM= ---- × 10 3 ( cm 3 )σM = the longitudinal midship bending moment in kNm from Ch.1 Sec. 3= sagging or hogging bending moment= hollow landing or crest landing bending moment= maximum still water + wave bending moment for high speed displacement craft and semi-planing craftin the displacement mode= maximum total moment for hydrofoil on foilsσ =175 f 1 N/mm 2 in general.Guidance note:Simultaneous end impacts over a hollow are considered less frequent and giving lower moments than the crestlanding.Need not be investigated if deck buckling resistance force is comparable to that of the bottom.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---B 200 Effective section modulus201 Where calculating the moment of inertia and section modulus of the midship section, the effectivesectional area of continuous longitudinal strength members is in general the net area after deduction ofopenings.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.4 – Page 23Superstructures which do not form a strength deck are not to be included in the net section. This applies alsoto deckhouses and bulwarks.202 The effect of openings are assumed to have longitudinal extensions as shown by the shaded areas inFig.2, i.e. inside tangents at an angle of 30° to each other. Example for transverse section III:b III = b' + b’’ + b’’’203 For twin hull vessels the effective breadth of wide decks without longitudinal bulkhead support will beconsidered separately.B 300 Hydrofoil on foils301 For hydrofoils in addition to the calculation for the midship section, the sections in way of the foils arerequired to be checked.B 400 Longitudinal structural continuity401 The scantling distribution of structures participating in the hull girder strength in the various zones of thehull is to be carefully worked out so as to avoid structural discontinuities resulting in abrupt variations ofstresses.402 At ends of effective continuous longitudinal strength members in deck and bottom region large transitionbrackets are to be fitted.Fig. 2Effect of openingsB 500 Openings501 A keel plate for docking is normally not to have openings. In the bilge plate, within 0.5 L amidships,openings are to be avoided wherever practicable. Any necessary openings in the bilge plate are to be kept clearof a bilge keel.502 Openings in strength deck are wherever practicable to be located well clear of the craft’s side and hatchcorners.503 Openings in strength members should generally have an elliptical form. Larger openings in deck may beaccepted with well rounded corners and are to be situated as near to the craft's centreline as practicable.504 For corners with rounded shape the radius is not to be less than:r = 0.025 B dk (m)B dk = breadth of strength deck.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.4 – Page 24r need not be taken greater than 0.1 b (m) where b = breadth of opening in m. For local reinforcement of deckplating at circular corners, see Sec. 5 B.505 Edges of openings are to be smooth. Machine flame cut openings with smooth edges may be accepted.Small holes are to be drilled.506 Studs for securing small hatch covers are to be fastened to the top of a coaming or a ring of suitablethickness welded to the deck. The studs are not to penetrate the deck plating.C. Shear StrengthC 100 Cases to be investigated101 If doors are arranged in the craft's side, the required sectional area of the remaining side plating will bespecially considered.102 If rows of windows are arranged below strength deck, sufficient horizontal shear area must be arrangedto carry down the midship tension and compression.103 In these and other locations with doubtful shear areas, allowable shear stress may be taken as:allowable bending stressτ = ----------------------------------------------------------3D. Cases to be InvestigatedD 100 Inertia induced loads101 Transversely framed parts of forebody are to be checked for the axial inertia force given in Ch.1 Sec.3A700:F L = Δa l (kN)a l = maximum surge acceleration, not to be taken less than:V0.4 g for ------- ≥ 5L0.2 g forV------- ≤ 3LVlinear interpolaton of a l for 3 < ----- < 5lThe distribution of stresses will depend on instantaneous forward immersion and on location of cargo.102 Bottom structure in way of thrust bearings may need a check for the increased thrust when vessel isretarded by a crest in front.103 Allowable axial stress and associated shear stresses will be related to the stresses already existing in theregion.104 For passenger craft, a separate analysis is to be performed to investigate the structural consequence whensubject to the collision load as given in the International Code of Safety for High-Speed Craft, paragraph 4.3.3(see Ch.7 Sec.1 B300).Guidance note:Inertia forces from the collision deceleration should be considered for shear and buckling in the foreship area, and forthe forces acting on the supporting structure for cargo.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---E. Transverse Strength of Twin Hull CraftE 100 Transverse strength101 The twin hull connecting structure is to have adequate transverse strength related to the design loads andmoments given in Ch.1.102 When calculating the moment of inertia, and section modulus of the longitudinal section of theDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.4 – Page 25connecting structure, the effective sectional area of transverse strength members is in general to be taken as thenet area with effective flange after deduction of openings.The effective shear area of transverse strength members is in general to be taken as the net web area afterdeduction of openings.E 200 Allowable stresses201 The equivalent stress is defined as:σ c = σ2 x + σ2 y – σ xσ y + 3τ 2σ x = total normal stress in x-directionσ y = total normal stress in y-directionτ = total shear stress in the xy-plane.By total stress is meant the arithmetic sum of stresses from hull girder and local forces and moments.202 The following total stresses are normally acceptable:— normal stress:σ = 160 f 1 (N/mm 2 )— mean shear stress:τ = 90 f 1 (N/mm 2 )— equivalent stress:σ e = 180 f 1 (N/mm 2 ).DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.5 – Page 26SECTION 5PLATING AND STIFFENERSA. GeneralA 100 Introduction101 In this section the general requirements for plate thicknesses and local strength of panels of aluminiumalloy are given.102 Buckling strength requirements are related to longitudinal hull girder stresses. Panels subjected to othercompressive, shear or biaxial stresses will be specially considered.Table A1 Allowable bending stressesItem Plate Stiffener(N/mm 2 )Bottom, slamming load 200 f 1 180 f 1Bottom, sea load 180 f 1 160 f 1Side 180 f 1 160 f 1Deck 180 f 1 160 f 1Flat cross structure, slamming load 200 f 1 180 f 1Flat cross structure, sea load 180 f 1 160 f 1Bulkhead, collision 180 f 1 160 f 1Superstructure/deckhouse front 160 f 1 140 f 1Superstructure/deckhouse side/deck 180 f 1 160 f 1Bulkhead, watertight 220 f 1 200 f 1Tank bulkhead 180 f 1 160 f 1A 200 Definitions201 Symbols:t = rule thickness of plating in mmZ = rule section modulus of stiffener in cm 3s = stiffener spacing in m, measured along the platingl = stiffener span in m, measured along the top flange of the member.The depth of stiffener on crossing panel may be deducted when deciding the span.For curved stiffeners l may be taken as the chord lengthp = design pressure in kN/m 2 as given in Ch.1 Sec.2σ = nominal allowable bending stress in N/mm 2 due to lateral pressure (see Table A1)f 1 = see Sec.l A202τ = nominal allowable shear stress in N/mm 2 .A 300 Allowable stresses301 Maximum allowable bending stresses in plates and stiffeners are to be according to Table A1.B. PlatingB 100 Minimum thicknesses101 The thickness of structures is in general not to be less than:tt 0 + kL= ----------------fs---- (mm)s Rf =σ fσ-------- f240= yield stress in N/mm 2 at 0.2% offset for unwelded alloy.σ f is not to be taken greater than 70% of the ultimate tensile strengthDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.5 – Page 27ss Rs-----s Rt 0 and k according to Table B1.B 200 Bending201 The general requirement for thickness of plating subject to lateral pressure is given by:C= actual stiffener spacing (m)= basic stiffener spacing (m)=2100 ( + L)--------------------------1000is not to be taken less than 0.5 or greater than 1.0.Table B1 Values of t 0 and kItem t 0 kBottom, bilge and side to loaded water line 4.0 0.03Shell plating Side above loaded water line 3.5 0.02Bottom aft in way of rudder, shaft brackets etc. 10.0 0.10Strength deck weather part forward of amidships 3.0 0.03Strength deck weather part aft of amidships 2.5 0.02Inner bottom 3.0 0.03Deck and inner bottomCar deck 4.0 0.03platingAccommodation deck 2.0 0.02Deck for cargo 4.0 0.03Superstructure and deckhouse decks 1.0 0.01Collision bulkhead 3.0 0.03Tank bulkhead 3.0 0.03Bulkhead plating Other watertight bulkheads 3.0 0.02Superstructure and deckhouse front 3.0 0.01Superstructure and deckhouse sides and aft 2.5 0.01Other structuresFoundations 3.0 0.08Structures not mentioned above 3.0 0ts Cp= ------------- (mm)σ= correction factor for aspect ratio (= s/l) of plate field and degree of fixation of plate edges given in TableB2.202 The thickness requirement for a plate field clamped along all edges and with an aspect ratio ≤ 0.5:t22.4s p= -------------------- (mm).σB 300 Slamming301 The bottom plating is to be strengthened according to the requirements given in 302 to 303.302 The thickness of the bottom plating is not to be less than:t=22.4k r s P----------------------------- sl(mm)σ slk r = correction factor for curved plates= 1 – 0.5 s r - r = radius of curvature in mP sl = as given in Ch.1 Sec.2DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.5 – Page 28σ sl = 200 f 1 (N/mm 2 ).303 Above the slamming area the thickness may be gradually reduced to the ordinary requirement at side.For craft with rise of floor, however, reduction will not be accepted below the bilge curvature or chine.Table B2 Values of CDegree of fixation of plate edges Aspect ratio < 0.5 Aspect ratio = 1.0σ l σ s σ x σ y σ l σ s σ x σ yClamped along all edges 500 342 75 250 310 310 130 130Longest edge clamped, shortest 500 0 75 250 425 0 140 200edge simply supportedσ l = stress at midpoint of longest edge.σ s = stress at midpoint of shortest edge.σ x = maximum field stress parallel to longest edge.= maximum field stress parallel to shortest edge.σ yC. StiffenersC 100 Bending101 The section modulus of longitudinals, beams, frames and other stiffeners subjected to lateral pressure isnot to be less than:Z=m l 2 sp--------------- ( cm 3 )σm = bending moment factor depending on degree of end constraints and type of loading, see also Sec. 6Table B2.The m-values are normally to be as given in Table C 1.The m-values may have to be increased after special consideration of rotation/deflection at supports or variationin lateral pressure.The m-values may be reduced, provided acceptable stress levels are demonstrated by direct calculations.102 The requirement in 101 is to be regarded as a requirement about an axis parallel to the plating. As anapproximation, the requirement for standard section modulus for stiffeners at an oblique angle with the platingmay be obtained if the formula in 101 is multiplied by the factor:α1-----------cosα= angle between the stiffener web plane and the plane perpendicular to the plating.For α-values less than 12° corrections are normally not necessary.103 When several members are equal, the section modulus requirement may be taken as the averagerequirement for each individual member in the group. However, the requirement for the group is not to be takenless than 90% of the largest individual requirement.104 Front stiffeners of superstructures and deckhouses are to be connected to deck at both ends with aconnection area not less than:0.07a = ----------lsp ( cm 2 )f 1Side and after end stiffeners in the lowest tier of erections are to have end connections.Table C1 Values of mItemmContinuous longitudinal members 85Non-continuous longitudinal members 100Transverse members 100Vertical members, ends fixed 100Vertical members, simply supported 135Bottom longitudinal members 85DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.5 – Page 29Table C1 Values of m (Continued)ItemmBottom transverse members 100Side longitudinal members 85Side vertical members 100Deck longitudinal members 85Deck transverse members 100Watertight bulkhead stiffeners, fixed ends 65Watertight bulkhead stiffeners, fixed one end (lower) 85Watertight bulkhead stiffeners, simply supported ends 125Watertight bulkhead horizontal stiffeners, fixed ends 85Watertight bulkhead stiffeners, fixed one end (upper) 75Watertight bulkhead horizontal stiffeners, simply supported 125Tank cargo bulkhead, fixed ends 100Tank cargo bulkhead, simply supported 135Deckhouse stiffeners 100Casing stiffeners 100C 200 Slamming201 The section modulus of longitudinals or transverse stiffeners supporting the bottom plating is not to beless than:m = 85 for continuous longitudinals= 100 for transverse stiffenersp sl = slamming pressure as given in Ch.1 Sec. 2σ sl =180 f 1 (N/mm 2 ).The shear area is not to be less than:A S =6.7( l – s)sp ---------------------------------- sl( cm 2 )τ sl =90 f 1 (N/mm 2 ).Z=m l 2 sp--------------------- sl( cm 3 )σ slτ slDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.6 – Page 30SECTION 6WEB FRAMES AND GIRDER SYSTEMSA. GeneralA 100 Introduction101 In this section the general requirements for simple girders and procedures for the calculations of complexgirder systems are given.A 200 Definitions201 Symbols:s = girder span in m. The web height of in-plane girders may be deductedb = breadth of load area in m (plate flange) b may be determined from Table A1p = design pressure in kN/m 2 according to Ch. 1 Sec.2P = design axial force in kNσ = nominal allowable bending stress in N/mm 2 due to lateral pressureτ = nominal allowable shear stress in N/mm 2σ c = critical buckling stress in N/mm 2σ el = ideal elastic buckling stress in N/mm 2Z = rule section modulus in cm 3A W = rule web area in cm 2A = rule cross-sectional area in cm 2t w = web thickness in mmh w = web height in mm= flange breadth in mm.b fA 300 Minimum thicknesses301 The thickness of structures are in general not to be less than:t 0 + kL st = ---------------- ---- ( mm)f s Rf =σ fss Rs-----s R= yield stress in N/mm 2 at 0.2% offset for unwelded alloy. σ f is not to be taken greater than 70% of theultimate tensile strength. For unwelded material, f may be taken as f 1 in Sec.2 Tables B1 to B3.= actual stiffener spacing in m= basic stiffener spacing in m=σ-------- f2402100 ( + L)--------------------------1000is not to be taken less than 0.5 or greater than 1.0.t 0 and k according to Table A2.Table A1 Breadth of load areaFor ordinary girders b = 0.5 (l 1 + l 2 (m)l 1 and l 2 are the spans in m of the supported stiffenersFor hatch side coamings b = 0.2 (B 1 - b 2 ) (m)B 1 = breadth of craft in m measured at the middle of the hatchwayb 2 = breadth of hatch in m measured at the middle of the hatchwayFor hatch end beams b = 0.4 b 3 (m)b 3 = distance in m between hatch end beam and nearest deep transverse girder or transversebulkheadDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.6 – Page 31Table A2 Values of t 0 and kItem t 0 kBottom centre girder 3.0 0.05Bottom side girders, floors, brackets and stiffeners 3.0 0.03Girders and Side, deck and bulkhead longitudinals girders and stiffeners outside the peaks 3.0 0.02stiffenersPeak girders and stiffeners 3.0 0.03Longitudinals 3.0 0.03Double bottom floors and girders 3.0 0.02Other structuresFoundations 3.0 0.08Structures not mentioned above 3.0 0A 400 Allowable stresses401 Maximum allowable bending stresses and shear stresses in web frames and girders are to be accordingto Table A3.Table A3 Allowable stressesItemWeb frames and girdersBending stress(N/mm 2 )Shear stress(N/mm 2 )Equivalent stress(N/mm 2 )Dynamic load 180 f 1 90 f 1 200 f 1Sea/static load 160 f 1 90 f 1 180 f 1For watertight bulkheads (excluding the collision bulkhead), allowable stresses may be increased to 200 f 1 , 100f 1 and 220 f 1 for bending, shear and equivalent stresses, respectively.A 500 Continuity of strength members501 Structural continuity is to be maintained at the junction of primary supporting members of unequalstiffness by fitting well rounded brackets.Brackets are to extend to the nearest stiffener, or local plating reinforcement is to be provided at the toe of thebracket.502 Where practicable, deck pillars are to be located in line with pillars above or below.503 Below decks and platforms, strong transverses are to be fitted between verticals and pillars, so that rigidcontinuous frame structures are formed.B. Web Frames and GirdersB 100 General101 The requirements for section modulus and web area given in 400 are applicable to simple girderssupporting stiffeners or other girders exposed to linearly distributed lateral pressure. It is assumed that thegirder satisfies the basic assumptions of simple beam theory and that the supported members are approximatelyevenly spaced and similarly supported at both ends. Other loads will have to be specially considered.102 When boundary conditions for individual girders are not predictable due to dependence of adjacentstructures, direct calculations according to the procedures given in Sec. 9 D will be required.103 The section modulus and web area of the girder are to be taken in accordance with requirements as givenin the following. Structural modelling in connection with direct stress analysis is to be based on the samerequirements when applicable. Note that such structural modelling will not reflect the stress distribution at localflange cutouts or at supports with variable stiffness over the flange width. The local effective flange which maybe applied in stress analysis is indicated for construction details in various Classification Notes on «strengthanalysis of hull structures)».B 200 Effective flange201 The effective plate flange area is defined as the cross-sectional area of plating within the effective flangewidth. Continuous stiffeners may be included with 50% of their cross-sectional area. The effective flange widthbe is determined by the following formula:b e = C b (m)C= as given in Table B1 for various numbers of evenly spaced point loads (r) on the span.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.6 – Page 32If the above method of calculation is used for strength members which support corrugations perpendicular tothe span of the strength member, C is to be reduced by 90%.Table B1 Values of Ca/b 0 1 2 3 4 5 6 ≥ 7C (r ≥ 6) 0.00 0.38 0.67 0.84 0.93 0.97 0.99 1.00C (r = 5) 0.00 0.33 0.58 0.73 0.84 0.89 0.92 0.93C (r = 4) 0.00 0.27 0.49 0.63 0.74 0.81 0.85 0.87C (r ≤ 3) 0.00 0.22 0.40 0.52 0.65 0.73 0.78 0.80a = distance between points of zero bending moments= S for simply supported girders= 0.6 S for girders fixed at both ends.202 The effective plate area is not to be less than the effective area of the free flange within the followingregions:— ordinary girders: total span— continuous hatch side coamings and hatch end beams: length and breadth of the hatch, respectively, and anadditional length of 1 m at each end of the hatch corners.B 300 Effective web301 Holes in girders will generally be accepted, provided the shear stress level is acceptable and the bucklingstrength is sufficient. Holes are to be kept well clear of end of brackets and locations where shear stresses arehigh.B 400 Strength requirements401 The section modulus for girders subjected to lateral pressure is not to be less than:Z =mS 2 bp----------------σ( cm 3 )σ =160 f 1 (maximum)m = bending moment factor, m-values in accordance with 403 may be applied.402 The effective web area of girders subjected to lateral pressure is not to be less than:10( k s Sbp – ar)A W = ------------------------------------ ( cm 2 )τk s = shear force factor.k s -values in accordance with 403 may be applieda = number of stiffeners between considered section and nearest supportr = average point load in kN from stiffeners between considered section and nearest supportτ =90 f 1 (maximum).The a-value is in no case to be taken greater than -----------n + 14n = number of supported stiffeners on the girder span. The web area at the middle of the span is not to beless than 0.5 A W .403 The m- and k s -values referred to in 401 and 402 may be calculated according to general beam theory. InTable B2 m- and k s -values are given for some defined load and boundary conditions. Note that the greatest m-value is to be applied to simple girders. For girders where brackets are fitted or the flange area has been partlyincreased due to large bending moment, a smaller m-value may be accepted outside the strengthened region.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.6 – Page 33Table B2 Values of m and k sLoad and boundary conditions Bending moment and shear force factorsPositions 1231 2 3m 1 m 2 m 3Support Field Support ks 1 — ks 3850.5042850.500.38 701.250.630.50 125 0.50650.30431000.700.20 601350.800.33 130 0.67404 The m- and k s -values referred to in 401 and 402 are normally to be as given in Table B3 for the variousstructural items.Table B3 Values of m and ks for various structural itemsItem m k sWeb frames 100 0.63Bottom: Floors 100 0.63Longitudinal girders 100 0.63Longitudinal girders 100 0.54Side:Web frames, upper end 100 0.54Web frames, lower end 100 0.72Deck girders 100 0.63Horizontal girders 100 0.54Bulkhead: Vertical girders, upper end 100 0.54Vertical girders, lower end 100 0.72405 The equivalent stress is not to exceed 180 f 1 N/mm 2 .B 500 Girder tripping brackets501 The spacing S T of tripping brackets is normally not to exceed the values given in Table B4 valid forgirders with symmetrical face plates. For others the spacing will be specially considered.Tripping brackets are further to be fitted near the toe of bracket, near rounded corner of girder frames and inline with any cross ties.502 The tripping brackets are to be fitted in line with longitudinals or stiffeners, and are to extend the wholeheight of the web plate. The arm length of the brackets along the longitudinals or stiffeners, is not to be lessthan 40% of the depth of the web plate, the depth of the longitudinal or stiffener deducted. The requirementmay be modified for deep transverses.503 Tripping brackets on girders are to be stiffened by a flange or stiffener along the free edge if the lengthDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.6 – Page 34of the edge exceeds:0.06 t t (m)t t = thickness in mm of tripping bracket.The area of the stiffening is not to be less than:10 l t (cm 2 )l t = length in m of free edge.The tripping brackets are to have a smooth transition to adjoining longitudinals or stiffeners exposed to largelongitudinal stresses.Table B4 Spacing between tripping bracketsGirder typeS T (m)Bottom and deck transverses0.02 bStringers and vertical webs in generalfmaximum 6Longitudinal girders in generalLongitudinal girders in bottom and strength deck for L > 50m within 0.5 L amidships0.014 bStringers and vertical webs in tanks and machinery spacesfmaximum 4Vertical webs supporting single bottom girders and transversesIf the web of a strength member forms an angle with the perpendicular to the ship’s side of more than 10°,S T is not to exceed 0.007 b f .b f = flange breadth in mmS = distance between transverse girders in m.B 600 Girder web stiffeners601 The web plate of transverse and vertical girders are to be stiffened where:h w > 75 t w (mm)t w = web thickness in mm,with stiffeners of maximum spacing:s = 60 t w (mm)within 20% of the span from each end of the girder and where high shear stresses.Elsewhere stiffeners are required when:h w > 90 t w (mm)with stiffeners of maximum spacing:s = 90 t w (mm)For girders supporting other girders, the end requirements may have to be applied all over the span.602 Stiffeners are to be fitted along free edges of the openings parallel to the vertical and horizontal axis ofthe opening. Stiffeners may be omitted in one direction if the shortest axis is less than 400 mm and in bothdirections if length of both axes is less than 300 mm. Edge reinforcement may be used as an alternative tostiffeners.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.7 – Page 35SECTION 7PILLARS AND PILLAR BULKHEADSA. GeneralA 100 Introduction101 In this section requirements for pillars and for bulkhead stiffeners substituting pillars are given.A 200 Definitions201 Symbols:L, B, D, T, C B , see Ch.1.t = thickness of plating in mms = stiffener spacing in m, measured along platel = length of pillars, cross ties, bulkhead stiffeners etc. between effective supports normal to their axis in mI = smallest moment of inertia in cm 4 , including 40 x plate thickness as flange for bulkhead stiffenerA = cross-sectional area in cm 2 , including 40 x plate thickness for bulkhead stiffenerp = design pressure as given in Ch.1.B. PillarsB 100 Arrangement of pillars101 Where practicable, deck pillars are to be located in line with pillars above or below.If arrangement with pillars in line is not possible, deck beams or girders will have to be reinforced.102 Pillars or equivalent supports are to be arranged below deckhouses, windlasses, winches and other heavyweights.103 The engine room casing is to be supported.104 Doubters are to be fitted on deck and inner bottom, except in tanks where doublers are not allowed.Brackets may be used instead of doublers. Where pillar tension may occur, brackets are required.105 Structural reinforcement below pillars will be considered in the individual cases.B 200 Cross-section particulars201 The radius of gyration of a member is to be taken as:I a= moment of inertia as built in cm 4 about the axis perpendicular to the expected direction of bucklingA a = cross-sectional area as built in cm 2 .If the end conditions are different with respect to the principle axes of the member, the i-value may have to bechecked for both axes.B 300 Pillar scantlings301 The cross-sectional area of members subjected to compressive loads is not to be less than:η =Plikk--------------- minimum 0,3 l1 + - iiA==I----- a( c m )A a10 P---------- ( cm 2 )ησ c= axial load in kN as given for various strength members in 302 and 303. Alternatively, P may beobtained from direct stress analysis. See Sec.9 D= length of member in m= radius of gyration in cm= 0.7 in generalDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.7 – Page 36= 0.6 when design loads are primarily dynamicσ c ==σ E when σ Eσ Fσ F< -----2σ F 1 – --------- 4σ E when σ > -----σ FE 2σ E =σ F = minimum upper yield stress of material in N/mm 2E = modulus of elasticity for aluminium = 69 000 N/mm 2 .The formula given for σ E is based on hinged ends and axial force only.If, in special cases, it is verified that one end can be regarded as fixed, the value of σ E may be multiplied by 2.If it is verified that both ends can be regarded as fixed, the value of σ E may be multiplied by 4.In case of eccentric force additional end moments or additional lateral pressure, the strength member is to bereinforced to withstand bending stresses.302 The nominal axial force in pillars is normally to be taken as:P = n FnFπ 2 iE------------ 2 (N ⁄ mm100 l2 )= number of decks above pillar. In case of a large number of decks (n > 3), a reduction in P will beconsidered based upon a special evaluation of load redistribution= the force contribution in kN from each deck above and supported by the pillar in question given by:F = p A D (kN)p = design pressure on deck as given in Ch.1 Sec.2A D = deck area in m 2 supported by the pillar, normally taken as half the sum of span of girders supported,multiplied by their loading breadth.For centre line pillars supporting hatch end beams (see Fig.1 and Fig.2):A D ==4A ( 1 + A 2 ) b 1---- when transverse beamsB4A ( 3 + A 4 + A 5 ) b 1---- when longitudinalsBb 1= distance from hatch side to craft's side.303 The nominal axial force in cross ties and panting beams is normally to be taken as:P = e b p (kN)ebp= mean value of spans in m on both sides of the cross tie= load breadth in m= the larger of the pressures in kN/m 2 on either side of the cross tie (e.g. for a side tank cross tie, thepressure head on the craft's side may be different from that on the longitudinal bulkhead).B 400 Pillars in tanks401 Hollow pillars are not accepted.402 Where the hydrostatic pressure may give tensile stresses in the pillars and cross members, their sectionalarea is not to be less than:A = 0.07 A dk p t (cm 2 )A dk = deck or side area in m 2 supported by the pillar or cross memberp t = design pressure, p in kN/m 2 giving tensile stress in the pillar.The formula may be used also tension control of panting beams and cross ties in tanks.Doubling plates at ends are not allowed.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.7 – Page 37C. Supporting BulkheadsC 100 General101 Bulkheads supporting decks are to be regarded as pillars. Compressive loads are to be calculated basedon supported deck area and deck design loading.102 Buckling strength of stiffeners are to be calculated as indicated in Sec.10 E101, assuming a plate flangeequal to 40 x the plate thickness when calculating I A , A and i.Local buckling strength of adjoining plate and torsional buckling strength of stiffeners are to be checked.Fig. 1Deck with transverse beamsFig. 2Deck with longitudinalsDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.8 – Page 38SECTION 8WELD CONNECTIONSA. GeneralA 100 Introduction101 In this section requirements for welding of aluminium alloys and various connection details are given.102 For general requirements for approval of welding of wrought aluminium alloys, see Pt.2 Ch.3 Sec.2.A 200 Welding particulars201 Welding at ambient air temperature of – 5°C or below is only to take place after special agreement.202 The welding sequence is to be such that the parts may as far as possible contract freely in order to avoidcracks in already deposited runs of weld. Where a butt meets a seam, the welding of the seam is to beinterrupted well clear of the junction and not be continued until the butt is completed. Welding of butt is tocontinue past the open seam and the weld be chipped out for the seam to be welded straight through.203 Welding procedures and welding consumables approved for the type of connection and parent materialin question, are to be used. See “Register of Approved Manufac-turers” and “Register of Type ApprovedProducts”.B. Types of Welded JointsB 100 Butt joints101 For panels with plates of equal thickness, the joints are normally to be butt welded with prepared edges.102 For butt welded joints of plates with thickness difference exceeding 2 mm, the thicker plate is normallyto be tapered. The taper is generally not to exceed 1:3.103 Welding against permanent or temporary backing is to be specially considered with respect to fatigue,non-destructive examination and any risk of crevice corrosion.B 200 Tee or cross joints201 The connection of girder and stiffener webs to plate panels, including plating abutting to other platepanels, is normally to be made by fillet welds as indicated in Fig.1.Fig. 1Tee or cross jointsWhere the connection is highly stressed, the edge of the abutting plate may have to be bevelled to give deep orfull penetration welding. Where the connection is moderately stressed, intermittent welds may be used. Withreference to Fig.2, the various types of intermittent welds are as follows:— chain weld— staggered weld— scallop weld (closed).DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.8 – Page 39Fig. 2Intermittent welds202 Double continuous welds are required in the following connections irrespective of the stress level:— oiltight and watertight connections— connections in foundations and supporting structures for machinery— all connections in way of the steering gear arrangement— connections in rudders, except where access difficulties necessitate slot welds— all connections in a region above the propeller extending a radius of minimum 1.5 x the propeller diameter— connections at supports and ends of stiffeners, pillars, cross ties and girders— centreline girder to keel plate— all structures in ballast tanks and other tanks holding corrosive liquids.C. Size of ConnectionsC 100 Fillet welds, general101 Unless otherwise stated, the requirements for throat thicknesses are given for double continuous filletwelds. It is assumed that the welding consumables used will give weld de posits with yield strength accordingto Pt.2 Ch.3 Sec.2 Table C2.102 The throat thickness of double continuous fillet weld is not to be less than:t = 0.42 t 0 (mm)t 0 = thickness in mm of thinner of the plates.The throat thickness is not to be less than 2 mm.The throat thickness may have to be increased when considered necessary due to a high stress level.103 The throat thickness of intermittent welds is to be as required in 102 for double continuous weldsprovided the welded length is not less than:— 80% of total length in the slamming area forward of amidships— 60% of total length for connections in tanks and bottom aft of amidships— 45% of total length for connections elsewhere.t 0 = as given in 102.Total length means total length of double continuous welds.104 Double continuous welds may be required in:— slamming area— engine room area— adjacent to tanks.C 200 Fillet welds and penetration welds subject to high tensile stresses201 In structural parts where high tensile stresses (> 50 N/mm 2 ) act through an intermediate plate (see Fig.1)DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.8 – Page 40increased fillet welds or penetration welds are to be used. Examples of such structures are:— transverse bulkhead connection to the double bottom— structural elements in double bottoms below bulkheads— transverse girders to longitudinal bulkheads.202 The throat thickness of double continuous weld is not to be less than:t 0.35 -----σ r= + --- – 1 55t 0 t0 (mm)σ = calculated maximum tensile stress in abutting plate in N/mm 2= minimum 50 N/mm 2r = root face in mmt 0 = thickness in mm of thinner of the plates.C 300 End connections of girders, pillars and cross ties301 The weld connection area of bracket to adjoining girders or other structural parts is to be based on thecalculated normal and shear stresses. Double continuous welding is to be used. Where high tensile stresses areexpected, welding according to 200 is to be applied.302 The end connections of simple girders are to satisfy the requirements for section modulus given for thegirder in question.Where shear stresses in web plates exceed 35 f w N/mm 2 , double continuous boundary fillet welds are to havethroat thickness not less than:t=τ t------------- 0(mm)80 f wτ = calculated shear stress in N/mm 2t 0 = thickness of abutting plate.f w = material factor for weld deposit= σ f w /240σ fw = yield strength in N/mm 2 of weld deposit.303 End connections of pillars and cross ties are to have a weld area not less than:a=0.14Ap------------------ (cm 2 )f wA = load area in m 2 for pillar or cross tiep = design pressure in kN/m 2 as given in Ch.1f w = as given in 302.C 400 End connections of stiffeners401 Stiffeners may be connected to the web plate of girders in the following ways:— welded directly to the web plate on one or both sides of the frame— connected by single- or double-sided lugs— with stiffener or bracket welded on top of frame— a combination of the above mentioned connections.In locations with great shear stresses in the web plate, a double-sided connection or a stiffening of theunconnected web plate edge is normally required. A double-sided connection may be taken into account whencalculating the effective web area.402 The connection area at supports of stiffeners is normally not to be less than:c = factor as given in Table C 1k = 0.125 for pressure acting on stiffener side= 0.1 for pressure acting on opposite sidel = span of stiffener in mck( l – 0.5s) spa 0 = -------------------------------------- (cm 2 )f wDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.8 – Page 41s = spacing between stiffeners in mp = design pressure in kN/m 2 as given in Ch.1f w = as given in 302.Table C1 c-factorsType of connectionStiffener or bracket on top of stiffener(see Fig. 3)None Single-sided Double-sideda 1.00 1.25 1.00b 0.90 1.15 0.90c 0.80 1.00 0.80403 Various standard types of connections are shown in Fig.3.Other types of connection will be considered in each case.STIFFNER ORBRACKETaTHIS DISTANCE SHOULD BEAS SHORT AS POSSIBLESTIFFNER ORBRACKETbLUGSTIFFNER ORBRACKETcFig. 3End connections404 Connection lugs are to have a thickness not less than the web plate thickness.405 Lower ends of peak frames are to be connected to the floors by a weld area not less than:a=0.105 l sp------------------------- (cm 2 )f wl, s p and f w = as given in 402.406 Bracketed end connections as mentioned in 407 and 408 are to have a weld area not less than:kZa = -------- (cm 2 )f w hZ = section modulus of stiffener in cm 3h = stiffener height in mmk = 24 for connections between supporting plates in double bottoms and transverse bottom frames orreversed frames= 25 for connections between the lower end of main frames and brackets= 15 for brackets fitted at lower end of tween deck frames, and for brackets on stiffeners= 10 for brackets on tween deck frames carried through the deck and overlapping the underlying bracketf w = as given in 302.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.8 – Page 42407 Brackets between transverse deck beams and frames or bulkhead stiffeners are to have a weld area notless than:a = 0.41 Z t b (cm 2 )t b = thickness in mm of bracketZ = as defined in 406.408 The weld area of brackets to longitudinals is not to be less than the sectional area of the longitudinal.Brackets are to be connected to bulkhead by a double continuous weld.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.9 – Page 43SECTION 9DIRECT STRENGTH CALCULATIONSA. GeneralA 100 Introduction101 In the preceding sections the scantlings of the various primary and secondary hull structures (girdersystems, stiffeners, plating) have been given explicitly, based on the design principles outlined in Ch.1 Sec.l.In some cases direct strength or stress calculations have been referred to in the text. The background andassumptions for carrying out such calculations in addition to or as a substitute to the specific requirements aregiven in this section. Load conditions, allowable stresses and applicable calculation methods are specified.A 200 Application201 The application of direct stress analysis is governed by:a) Required as part of rule scantling determination. In such cases where simplified formulations are not ableto take into account special stress distributions, boundary conditions or structural arrangements withsufficient accuracy, direct stress analysis has been required in the rules.b) As alternative basis for the scantlings. In some cases direct stress calculations may give reduced scantlings,especially when optimisation routines are incorporated.B. PlatingB 100 General101 Normally direct strength analysis of laterally loaded plating is not required as part of rule scantlingestimation.102 Buckling control of plating subjected to large in-plane compressive stresses is specified in Sec. 4.B 200 Calculation procedure201 Laterally loaded local plate fields may be subject to direct stress analysis applying general 3-dimensionalplate theory or finite element calculations. The calculations should take into account the boundary conditionsof the plate field as well as membrane stresses developed during deflection of the plate.B 300 Allowable stresses301 When combining the calculated local bending stress with in-plane stresses the equivalent stress σ e in themiddle of a local plate field is not to exceed 240 f 1 N/mm 2 . The local bending stress in the same point is in nocase to exceed 160 f 1 N/mm 2 .σ e = σ2 x + σ2 y – σ xσ y + 3τ 2σ xσ yτ= aritmetic sum of local bending stress and in-plane stresses in the x-direction= aritmetic sum of local bending stress and in-plane stresses in the y-direction= shear stress in the xy-plane.302 The final thickness is not, however, to be less than the minimum thickness given in Sec.1 for the structurein question.C. StiffenersC 100 General101 Direct strength analysis of stiffeners may be requested in the following cases:— stiffeners on supports with different deflection characteristics— stiffeners subjected to large bending moments transferred from adjacent structures at supports.102 Buckling control of stiffeners subjected to large axial, compressive stresses is specified in Sec.4.DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.9 – Page 44C 200 Calculation procedure201 The calculations are to reflect the structural response of the 2- or 3-dimensional structure considered.Calculations based on elastic beam theory may normally be applied, with due attention to:— boundary conditions— shear area and moment of inertia variations— effective flange— effects of bending, shear and axial deformations— influence of end brackets.C 300 Loads301 The local lateral loads are to be taken as specified in Ch.1 for the structure in question.C 400 Allowable stresses401 The allowable stress level is given in Table C1.Table C1 Allowable stress levelsNominal local bending stress σ = 160 f 1 N/mm 2Combined local bending stress or girder stress or longitudinal stress σ = 220 f 1 N/mm 2Nominal shear stress τ = 90 f 1 N/mm 2D. GirdersD 100 General101 For girders which are parts of a complex 2- or 3-dimensional structural system, a complete structuralanalysis may have to be carried out to demonstrate that the stresses are acceptable when the structure is loadedas described in 300.102 Calculations as mentioned in 101 may be requested to be carried out for:— bottom structures— side structures— deck structures— bulkhead structures— transverse frame structures— other structures when deemed necessary by the Society.103 In addition to the complex structures indicated above, direct strength calculations may also be performedon more simple girders in order to optimise scantlings.D 200 Calculation methods201 Calculation methods or computer programs applied are to take into account the effects of bending, shear,axial and torsional deformations.The calculations are to reflect the structural response of the 2- or 3-dimensional structure considered, with dueattention to boundary conditions.For systems consisting of slender girders, calculations based on beam theory (frame work analysis) may beapplied, with due attention to:— shear area variation— moment of inertia variation— effective flange.202 For deep girders, bulkhead panels, etc. where results obtained by applying the beam theory areunreliable, finite element analysis or equivalent methods are to be applied.D 300 Design load conditions301 The calculations are to be based on loads at design level as given in Ch.1. For sea-going conditionsrealistic combinations of external and internal dynamic loads are to be considered.The mass of deck structures may be neglected when less than 5% of the applied loads.302 For transverse web frame beam element analysis, the following combinations of load apply:— sea pressure on all elementsDET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.9 – Page 45— slamming pressure on bottom.If twin hull, the following three conditions are to be added:— slamming pressure on bottom from outside and sea pressure on hull outer side— slamming pressure on bottom from inside and sea pressure on tunnel side and tunnel top— slamming pressure on tunnel top and sea pressure on tunnel side and bottom from insideFor all load cases, deck load pressure from cargo, passengers etc. is to be added.D 400 Allowable stresses401 The equivalent stress is defined as:σ e = σ2 x + σ2 y – σ xσ y + 3τ 2σ xσ yτ= normal stress in x-direction= normal stress in y-direction= shear stress in the xy-plane.402 The longitudinal combined stress taken as the sum of hull girder and longitudinal bottom, side or deckgirder bending stresses, is normally not to exceed 190 f 1 N/mm 2 .403 For girders in general, the following stresses are normally acceptable:Normal stress:σ =160 f 1 N/mm 2 .Mean shear stress:τ =90 f 1 N/mm 2 for girders with one plate flangeτ =100 f 1 N/mm 2 for girders with two plate flanges.Equivalent stress:σ e =180 f 1 N/mm 2 .DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.10 – Page 46SECTION 10BUCKLING CONTROLA 100 Definitions101 Symbols:A. Generalt = thickness in mm of platings = shortest side of plate panel in ml = longest side of plate panel in m= length in m of stiffener, pillar etc.E = modulus of elasticity of the material= 0.69 · 10 5 N/mm 2 for aluminiumσ el = the ideal elastic (Euler) compressive buckling stress in N/mm 2σ f = minimum upper yield stress of material in N/mm 2 . Usually base material properties are used, but criticalor extensive weld zones may have to be taken into accountτ el = the ideal elastic (Euler) shear buckling stress in N/mm 2τ f = minimum shear yield stress of material in N/mm 2=σ------ f3σ c = the critical compressive buckling stress in N/mm 2τ c = the critical shear stress in N/mm 2σ a = calculated actual compressive stress in N/mm 2τ a = calculated actual shear stress in N/mm 2η = stability (usage) factor = σ a----- = ----σ cτ cZ n = vertical distance in m from the baseline or deckline to the neutral axis of the hull girder, whichever isrelevantZ a = vertical distance in m from the baseline or deckline to the point in question below or above the neutralaxis, respectively.102 Relationships:τ aσ c ==τ c ==σ el when σ el σ ---- fel 2τ el when τ elτ f< ---2τ fτ f 1 – --------- 4τ el when τ > ---τ fel 2Guidance note:When the required σ c or τ c is known, the necessary σ el or τ el will from the above expressions of the Johnson-Ostenfeldrelationship beσ cτσ el------------ c= and τK el = ------------J – 0K J – 0DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.10 – Page 47K J − 0 from Fig.1 or from formulaσ c or τ cK J− 0 = 1 ------------------------------- – 1 2–0.5( σ f or τ f ) Fig. 1Forσ----- c< 0.5, Kσ J – 1 = 1f---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---B 100 Longitudinal stresses101 See Ch.l Sec.3 A700.B. Longitudinal Buckling LoadC. Transverse Buckling LoadC 100 Transverse stresses101 Transverse hull stresses in compression may occur from:— transverse loads and moments in twin hull craft, see Sec. 4 E— supports of craft's side structure, see Sec. 6.D. PlatingD 100 Plate panel in uni-axial compression101 The ideal elastic buckling stress may be taken as:tσ el = 0.9 k E ------------- 2 (N/mm 2 )1000sFor plating with longitudinal stiffeners (in direction of compressive stress):8.4k = k l = ----------------- ψ + 1.1for (0 ≤ ψ ≤ 1)For plating with transverse stiffeners (perpendicular to compressive stress):sk = k s = c 1 + -2l2 2.1----------------- for (0 ≤ ψ ≤ 1)ψ + 1.1DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.10 – Page 48c = 2.50 when stiffeners are hollow profiles with s/l

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.10 – Page 49D 200 Plate panel in shear201 The ideal elastic buckling stress may be taken as:τ el=t0.9k t E------------- 2 (N/mm 2 )1000sk t = 5.34 + 4 s l -2The critical shear buckling stress is found from A102.202 The critical shear stress is to be related to the actual shear stresses as follows:η = 0.90 for craft's side and longitudinal bulkhead subject to hull girder shear forces=0.95 η G for local panels in girder webs when nominal shear stresses are calculated (τ a = Q/A)= η G for local panels in girder webs when shear stresses are determined by finite element calculations orsimilarη G = according to 102.Guidance note:The resulting thickness requirement will be:τ cτ a≥ ----ηt=4sτ----------------- c(mm)k t K J – 0τ c according to 202K J - 0 from Fig.1.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---D 300 Plate panel in bi-axial compression and shear301 For plate panels subject to bi-axial compression the interaction between the longitudinal and transversebuckling strength ratios is given by:σ ax = compressive stress in longitudinal direction (perpendicular to stiffener spacing s)σ ay = compressive stress in transverse direction (perpendicular to the longer side l of the plate panel)σ cx = critical buckling stress in longitudinal direction as calculated in 100σ cy = critical buckling stress in transverse direction as calculated in 100τ a and τ c are as given in 200σ axσ----------------- axσ ayσK--------------------------------------------------ay n –+≤ 1η xσ cx q η xη yσ cxσ cy q η yσ cy qη x , η y = 1.0 for plate panels where the longitudinal stress σ a (as given in Ch.1 Sec.3 A700) or other extremestress is incorporated and constitutes a major part in σ ax or σ ay= 0.95 η G other casesη G = according to 102K = c β ac and a are factors given in Table B1β = 1000 s t -σ---- fEDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.10 – Page 50n= factor given in Table B1Table B1 Factors for buckling strengthc a n1.0 < l/s < 1.5 0.78 – 0.12 1.01.5 ≤ l/s < 8 0.80 0.04 1.2η τ = η as given in 200.Only stress components acting simultaneously are to be inserted in the formula.For plate panels in structures subject to longitudinal stresses, such stresses are to be directly combined withlocal stresses to the extent they are acting simultaneously and for relevant load conditions. Otherwisecombinations based on statistics may be applied.Guidance note:For shear in combination with:— uni-axial compression:may be written:τ aq 1 ---------- 2= –η ττ cand with:— bi-axial compression, approximately:σ------- axor σ ay------- ≤ ( ησ cxσ x or η y )qcyσ-------------- ax1.1 σ ay-------------- ------------08 , σ ax------- σ ay+ – ------- ≤ qη xσ cxη yσ cyη xη yσ cxσ cyFor bi-axial compression alone q = 1.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---E. Stiffeners in Direction of CompressionE 100 Lateral buckling mode101 The ideal elastic lateral buckling stress may be taken as:i =I AĀ ---Eσ el = 10-------------------- 100 l 2 (N/mm 2 ) īI A = moment of inertia in cm 4 about the axis perpendicular to the expected direction of bucklingA = cross-sectional area in cm 2 .When calculating I A and A, a plate flange equal to 0.8 times the spacing is included for stiffeners.The critical buckling stress is found from A102.The formula given for σ el is based on hinged ends and axial force only.Continuous stiffeners supported by equally spaced girders are regarded as having hinged ends when consideredfor buckling.In case of eccentric force, additional end moments or additional lateral pressure, the strength member is to bereinforced to withstand bending stresses.DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.10 – Page 51102 For longitudinals and other stiffeners in the direction of compressive stresses, the critical buckling stresscalculated in 101 is to be related to the actual compressive stress as follows:σ cσ a≥ -----ησ aηη b= calculated extreme compressive stress, or ordinary local load stress divided by η G from D100= 0.85 for continuous stiffeners.=1– η b , maximum 0.85 for single-span stiffenerssimultaneous bending moment at midspan= ----------------------------------------------------------------------------------------------------bending moment capacityGuidance note:The resulting maximum allowable slenderness will be:100 l 830 K J – 0= ------------ī σ cσ c=σ----- aηK J-0 from Fig. 1.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---E 200 Torsional buckling mode201 For longitudinals and other stiffeners in the direction of compressive stresses, the ideal elastic bucklingstress for the torsional mode may in general be calculated from formulae in Rules for Classification of ShipsPt.3 Ch.1 Sec.14.202 The critical buckling stress as found from 201 and A102 is not to be less than:σ aη= calculated extreme compressive stress, or ordinary local load stress divided by η G from D100= 0.85 in general= 0.8 when the adjacent plating is allowed to buckle in the elastic mode, according to G.Guidance note:To avoid torsional buckling the height of flats should not exceed:σ cσ a≥ -----ηt w = thickness of web in mmσ aσ c = -----ηK J - 0 from Fig.1.h wFor flanged profiles, 1 < ----- < 3:b fMinimum flange breadth may be taken as:For symmetrical flanges:140h w = t w----------------- (mm)σ------------ cK J – 0For unsymmetrical flanges:b f = 5lσ------------ c(mm)K J – 0DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.10 – Page 52σ aσ c = -----ηK J − 0 = according to Fig.1h w = height of web in mm.b f=3.5 lσ------------ c(mm)K J – 0---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---E 300 Web and flange buckling301 The σ el -value required for the web buckling mode may be taken as:σ el 3.8E t w----- 2 =( N ⁄ mm 2 )h wt w , h w = web thickness and height in mm.302 The ideal elastic buckling stress of flange of angle and tee stiffeners may be calculated from thefollowing formula:= flange thickness in mm= flange width in mm for angles, half the flange width for T-sections.303 The critical buckling stress σ c found from A102 is not to be less than as given in 202.t fb fGuidance note:σ el 0.38 E t f---- 2 =( N ⁄ mm 2 )b f— Web thickness, see plating with stiffener in direction of compression stress, D103.— Flange width from web:140b f < t f----------------- (mm)σ------------ cK J – 0σ c = according to 202K J − 0 = according to Fig.1---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---F. Stiffeners Perpendicular to Direction of CompressionF 100 Moment of inertia of stiffeners101 For stiffeners supporting plating subject to compressive stresses perpendicular to the stiffener directionthe moment of inertia of the stiffener section (including effective plate flange) is not to be less than:lst= span in m of stiffener= spacing in m of stiffeners= plate thickness in mmI=0.81σ aσ el l 4 s-------------------------------- ( cm 4 )tσ el =σ------------ cK J – 0DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.10 – Page 53σ aσ c = ----------0.85σ a = calculated extreme compressive stress, or ordinary local load stress divided by η G from D100K J − 0 =according to Fig.1.G. Elastic Buckling of Stiffened PanelsG 100 Elastic buckling as a design basis101 Elastic buckling may be accepted for plating between stiffeners when:— platingσ fσ el < ----, i.e. σ2 el = σ c— ησ c of stiffener in direction of compression > ησ el of plating.ησ c from E and A102. To be multiplied by η G for ordinary local load.ησ el from D and A102— there are no functional requirements prohibiting the deflections— extreme loads are used in the calculations.Guidance note:For the torsional buckling mode of flats may be takenσ el=0.385E t w----- 2 ( N ⁄ mm 2 )h w---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---G 200 Allowable compression201 The allowable compressive force in the panel may be increased from:P A = 0.l η p σ el (A p + A s ) (kN)to:P A = 0.l η p σ el (A p + A s ) +0.1( η sσ c – η pσ el ) b e----A b p+ A s (kN)η p , η s = η for plating and stiffener from D and E. η s to be multiplied by η G for ordinary local loadσ el , σ c = for plating and stiffener, respectively, from D and E. Ordinary effective flange is to be used forstiffenersA p , A s = area of plating and stiffener in cm 2b----- ebσ u= fraction of A p participating in the post-buckling stress increaseσ= u – σ------------------- elσ f – σ el= ultimate average stress of plating=σ el 1 0.375 σ f+ ------ – 2 σ el202 For transversely stiffened plating (compressive stress perpendicular to longest side l of plate panel) isσ u = σ el 1 c σ f+ ------ – 2σ elDET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.10 – Page 540.75c = -----------l- + 1sA s = 0resulting in:P A = 0.l η p σ u A p (kN).203 σ u may be substituted for σ el when calculating uniaxial compression and shear in D300.H. GirdersH 100 Axial load buckling101 For lateral, torsional, web and flange buckling, see E, Stiffeners in direction of compression.H 200 Girders perpendicular to direction of compression201 For transverse girders supporting longitudinals or stiffeners subject to axial compression stresses, theideal elastic buckling stress may be taken as:S = span of girder in ml = distance between girders in ms = spacing of stiffeners in mI a = moment of inertia of stiffener in cm 4I b = moment of inertia of transverse girder in cm 4t = plate thickness in mm= equivalent plate thickness of stiffener area in mmt aπ 2σ el = 1.38----------------------S 2 ( t + t a )I a I-------- bsl=stiffener area---------------------------------------stiffener spacingThe critical buckling stress σ c is found from A102.202 The critical buckling stress found from 201 and A102 is not to be less than:σ cσ a≥ -----ησ a = calculated compressive stressη =0.75.H 300 Buckling of effective flange301 Plating acting as effective flange for girders which support crossing stiffeners is to have a satisfactorybuckling strength.302 Compressive stresses arising in the plating due to local loading of girders are to be less than η G x thecritical buckling strength, see 303. When calculating the compressive stress the section modulus of the girdermay be based on a plate flange breadth equal to the distance between girders (100% effective flange).η G : see D100.303 The critical buckling strength is given in D101 and A102, when l = span of stiffener or distance fromgirder to eventual buckling stiffener parallel to the girder.304 Elastic buckling of deck plating may be accepted after special consideration.Reference is made to G.The additional P A , and the corresponding additional moment capacity, will, however, refer to a girder sectionwith effective width of deck plating = b e .DET NORSKE VERITAS AS

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.10 – Page 55H 400 Shear buckling of web401 See D200, for constant shear force over l.Guidance note:For variable shear force over l of panel, a reduced l may be considered in formula.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---DET NORSKE VERITAS AS

Rules for High Speed, Light Craft and Naval Surface Craft, January 2011 Amended July 2011, see page 3Pt.3 Ch.3 Sec.10 – Page 56DET NORSKE VERITAS AS