SECTION 1 - Boat Design Net

Pt B, Ch 7, Sec 23 Sailing yachts of monohull type3.1 Plating and stiffeners3.1.1 The slamming pressure, in kN/m 2 , considered as actingon the bottom of hull is to be not less than:p sl = 70 ⋅ --- Δ ⋅ KS2 ⋅ K 3 ⋅ a vrwhere:Δ : Displacement, in tonnesS r : Reference area, m 2 , equal to:S r = 0,7 ⋅Δ -- TK 2 : Factor accounting for slamming area, equal to:K 2 0 455 0,35, – 1 ,= , – ⋅ --------------------------7, + 1 , 7with:u 0 75u 0 75• K 2 ≥ 0,50 for plating• K 2 ≥ 0,45 for ordinary stiffeners• K 2 ≥ 0,35 for primary stiffenersK 3 = ( 50 – α d ) ⁄ ( 50 – α dCG ) ≤ 1where α dCG is the deadrise angle, in degrees,measured at LCG and α d is the deadrise angle,in degrees, between horizontal line and a referenceline defined in Fig 2 at the transversal sectionconsidered; α d is not to be taken greaterthan 50 degreesa v : Total vertical acceleration resulting from thesum of heave and pitch acceleration (refer toCh 5, Sec 1, [2.2.4]).3.1.2 As a rule, the slamming pressure is to be calculatedalong the ship, from center of gravity of the keel or the bulbkeel to fore part of ship.Longitudinal location of calculation points can be taken asindicated in Fig 3. The value of the total vertical accelerationa v is to be calculated at each calculation point P i .Figure 2 : Deadrise angleu = 100 ⋅ ---s S rwhere s is the area, in m 2 , supported by the element(plating, stiffener, floor or girder). For plating,the supported area is the spacing betweenthe stiffeners multiplied by their span, withouttaking for the latter more than three times thespacing between the stiffenersTT/2Reference line fordeadrise anglemeasurementdeadrise angle α dK 3 : Factor accounting for shape and deadrise of thehull, equal to:Figure 3 : Calculation points for slamming pressurePosition of keel gravity center0.1 L0.1 L 0.1 L 0.1 L 0.1 LPi Pi Pi Pi Pi wlX iA.P.0.5 F.P. xL WL140 Bureau Veritas Rules for Yachts July 2006 with February 2008 Amendments