Design, Manufacturing, and Testing of an Improved Watertight Door ...

Design, Manufacturing, and Testing 

of an Improved Watertight Door for 

Surface Ships 

& Stephen M. Copley, Edward W. Reutzel, Terri A. Merdes, and Dennis B. Wess 

Abstract 

Designed in the 1950s to be watertight during flooding and airtight under normal operating conditions, 

the Navy standard watertight door for surface ships is inexpensive to manufacture but 

expensive to properly install and maintain. Furthermore, by today’s requirements, it is too heavy. 

The need for a lightweight, affordable, low maintenance watertight door led to a collaborative project 

involving the Applied Research Laboratory at Penn State University, Naval Surface Warfare 

Center, Carderock Division, Ship Systems Engineering Station, and Northrop Grumman Corporation 

Newport News to design, fabricate, and test an improved watertight door for surface ships. The 

design and manufacturing of this door is entirely new and based on advances in laser cutting and 

welding technology. Its novel design reduces the number of dogs (latches) and linkages of the Navy 

standard watertight door, decreasing the weight of the complete door assembly from 290 to 213 lbs. 

The door is fabricated from corrosion resistant stainless steel, and its opening and closing forces are 

extremely low, reducing the potential for mechanical and gasket wear. Pending successful completion 

of certification testing and with technical warrant holder approval, the new door will offer an 

attractive choice for insertion by Acquisition Program Managers and Fleet Maintenance Managers. 

Introduction 

Navy watertight doors, hatches, and scuttles 

(commonly referred to as watertight closures) 

play a critical role in surface ship damage control. 

The current Navy standard quick acting 

watertight door (NSWTD) was developed from 

designs dating back to the 1950s or earlier. 

Common watertight door sizes and configurations 

are shared across most classes of surface 

ships. Approximately, 32,000 NSWTDs are 

currently in-service aboard combatants and 

amphibs across the fleet (Burton and Simunov 

2006). NSWTDs perform marginally in-service 

and are very expensive to maintain. Marginal 

performance is the result of obsolete design, materials 

susceptible to corrosion and wear, and 

& 2011, American Society of Naval Engineers 

DOI: 10.1111/j.1559-3584.2010.00282.x 

TECHNICAL PAPER 

defects introduced during door manufacturing 

and shipboard installation. 

An initial needs assessment for the new watertight 

door led to requirements for: 

& hydrostatic integrity 

& shock resistance 

& vibration resistance 

& fire performance 

& weight reduction 

& acceptable procurement and installation cost 

& significantly reduced maintenance cost 

& reduced total ownership cost 

& a domestic manufacturing base assuring a 

competitive environment 

2010 #4 & 93

Design, Manufacturing, and Testing of an Improved Watertight Door 

94 &2010 #4 

These requirements will be further elucidated in 

subsequent sections. From the outset, it was 

clear that the design should focus on a single 

watertight door configuration meeting specified 

size and pressure requirements. Of particular interest 

were the possibilities of applying the 

accuracy and high speed of automated laser cutting 

and welding in manufacturing the panel and 

frame, and also developing a hydraulically 

(water pressure) actuated seal system. 

Watertight Door Selection 

Initially, the intent was to develop a design and 

manufacturing methodology that would apply 

to all sizes and configurations of watertight closures; 

however, it soon became obvious that this 

scope was too broad to be accomplished with the 

available resources. It was decided to select a 

single watertight door configuration and, after 

the design and manufacturing methodology had 

been established on this door, to extend the 

principles to other door sizes and configurations. 

After consultation with the NAVSEA technical 

warrant holder for ship hull outfitting systems, 

engineering colleagues at the Naval Surface 

Warfare Center Carderock Division, Ship Systems 

Engineering Station, Philadelphia 

(NSWCCD), and Northrop Grumman Corporation 

Newport News (NGCNN), it was decided 

to attempt to design a replacement for the 26 in. 

66 in., quick acting, 10 psi NSWTD with a 

6 in. light (window). The 26 66 NSWTD configuration 

is the most widely used configuration 

in aircraft carriers and ships across the fleet. A 

quick acting door is one in which the dogs are 

simultaneously operated by a single handle 

through a series of linkages. The door configuration 

selected for replacement has eight dogs 

(latches) and two hinges. The weight of the 

10 psi NSWTD is 290 lbs (including door panel, 

frame, and associated hardware). Interior and 

exterior view assembly drawings of this watertight 

door are shown in Figure 1. 

& The NSWTD’s marginal performance is related 

to several design features: the NSWTD is 

made mostly of low carbon steel. It must be 

painted or powder coated and the painted 

surface must be constantly maintained to 

avoid rust. 

& The NSWTD is sealed by forcing a knife edge 

against a silicone rubber gasket as illustrated 

in Figure 2. The NSWTD must maintain its 

seal for water loading both on the interior and 

exterior sides. While loading on the exterior 

side of the panel forces the gasket against the 

knife edge, loading on the interior side forces 

it away from the gasket. This must be resisted 

by force applied by the dogs to the wedges in 

order to maintain contact between the knife 

edge and the gasket. These forces are large, 

and sources of mechanical wear. Also, to 

properly seat the knife edge on the gasket and 

avoid pinching it on the hinge side, a ‘‘yoking’’ 

hinge is required. 

& The lap-welded bulkhead installation concept 

for the NSWTD frame assembly can introduce 

distortion into the NSWTD door frame, resulting 

in high mechanical operating forces 

that frequently result in cascading secondary 

component failures. 

As shown in Figure 3, the frame is attached to the 

bulkhead by two lap welds requiring contact between 

the frame and the bulkhead; however, 

bulkheads are typically not flat. As a consequence, 

the knife edge may become wavy due to 

conformance with the existing bulkhead surface. 

Adjustment of the hinges and dogging mechanism 

during installation and frequent inspection 

and adjustment in-service are required to ensure 

that the knife edge maintains proper contact 

with the gasket. 

Initial Design Strategies forNewDoor 

On a stiffness per pound basis, reinforcing the 

panel sheet by welding angle irons on one side, 

cupping the rims, and indenting the sheet is not 

very efficient. Square or rectangular honeycomb 

panels, with the spacing and thickness of the face 

sheets properly sized, are more efficient in bending 

or uniform pressure loading because in crosssection 

they place the bulk of material at a 

greater distance from the neutral axis increasing 

the second moment of inertia. Honeycomb panel 

structures bonded by adhesives are often used in 

NAVAL ENGINEERS JOURNAL

Figure 1: Navy Standard Watertight Door (26 in. 66 in., Quick Acting, 10 psi Door with Window): (a) Interior Side and (b) Exterior Side (NAVSEA 1987) 

lightweight structures. Metallic honeycomb 

panels have been produced by brazing metallic 

alloy face sheets to the honeycomb. Using brazes 

to join metallic stiffeners to face sheets for use in 

a sea environment is undesirable: the chemical 

dissimilarity of the braze alloys to the metallic 

honeycomb panel creates a high risk of galvanic 

corrosion. 

It was recognized early in this project that laser 

welding and cutting could potentially provide an 

entirely new approach for fabricating metallic 

alloy honeycomb panels and frames for the new 

watertight door. Laser cutting is fast and very 

accurate. Face sheets could be autogenously 

welded to the honeycomb, i.e., welded without 

filler metal, at high speeds. Laser cut and welded 

panels could be fabricated from stainless steel 

greatly reducing the risk of corrosion. A number 

of domestic, commercial job shops were identi- 

fied that were capable of laser cutting and 

welding the new watertight door. The application 

of laser technology to the manufacturing of 

stainless steel watertight doors was identified as 

an important design strategy for the new door. 

Figure 2: Dog Detail 

(NAVSEA 1987) 

NAVAL ENGINEERS JOURNAL 2010 #4 &95


Figure 3: Edge Section 

of NSWTD Seal 

System Showing the 

Frame Lap Welded to 

the Bulkhead with Its 

Knife Edge Contacting 

the Gasket 

Figure 4: Hydraulically 

Actuated Seal 

and Plug-In-Hole Installation 

Concepts 

96 & 2010 #4 

PANEL 

FRAME 

WITH 

KNIFE 

EDGE 

A second important design strategy was to replace 

the dogs, wedges, knife edge, and 

compression gasket seal system of the NSWTD 

with a novel hydraulically actuated seal system. 

The initial concept is illustrated in Figure 4. 

Flooding the door on one side forces the hollow 

cylindrical gasket against the gap on the other 

side plugging it and vice versa. Unfortunately, 

this simple concept did not work due to the large 

dimensional changes in the gasket cavity when 

the door was loaded. Also, lab testing of early 

prototypes of the hollow oval seal configuration 

revealed that unacceptably high compressive 

forces were required to initially seat the seal to 

ensure watertight performance. This finding 

clarified the desirability of a seal design that did 

not require high initial compressive forces. In the 

end, the development of a hydraulically actuated, 

leak-free seal system became the most 

challenging design aspect of the project. 

Also illustrated in Figure 4 is the third important 

design strategy, which will be referred to as the 

PANEL 

GASKET 

GASKET 

LAP WELDS 

BULKHEAD 

FRAME BULKHEAD 

FILLET WELDS 

plug-in-hole frame. This strategy eliminates the 

influence of bulkhead waviness on the seal system. 

The plug-in-hole frame is designed to slide 

inside the hole cut in the bulkhead. It is attached 

to the bulkhead by two fillet welds. This improves 

upon the NSWTD design in which the 

frame is clamped and lap welded to the bulkhead. 

Lap welding the frame to the bulkhead 

causes the frame to conform to any ‘‘waviness’’ 

or ‘‘out-of-plane’’ condition of the existing 

bulkhead. 

In what follows, each of these strategies will be 

discussed in greater detail. 

LASER CUT AND WELDED DOOR PANEL AND 

FRAME 

At the heart of the new watertight door design is 

a laser cut and welded panel structure called 

LASCELL (patent pending). It can be described 

as a rectangular (including square) honeycomb 

of laser cut metallic stiffeners, mechanically interlocked, 

joined to laser cut face sheets by 

autogenous welds through the face sheets into 

the stiffeners, as illustrated in Figures 5 and 7. 

It soon became clear that cutting the stiffeners 

and face sheets with a laser was straightforward 

whereas welding such a structure was to be a 

challenge. Although it was possible to spot weld 

the face sheets to the stiffeners without distortion, 

even one continuous weld of face sheet to 

stiffener caused the panel to bend in fabrication 

of early prototypes. Multiple parallel continuous 

welds caused the panel to form a cylindrical 

shape with the cylinder axis lying parallel to the 

welds. 

The origin of the observed distortion can be explained 

as follows. When the face sheet was 

welded to the stiffener, the alloy melted locally 

and then resolidified as the laser beam moved 

past. As it resolidified, very hot melt at the weld 

was surrounded by unmelted solid that was 

much cooler because of the high speed of the laser 

beam. The resolidified melt, which was much 

hotter than the surrounding solid, shrank more 

due to thermal contraction upon cooling, result- 


ing in plastic deformation that caused the observed 

distortion. 

To fabricate the first LASCELL panel structure, 

the following procedure was developed. Laser 

cut stiffeners were assembled using a position 

fixture (an aluminum plate with an orthogonal 

grid of milled slots) to form the mechanically interlocked 

rectangular honeycomb. A face sheet 

was placed on the stiffeners and held in place by 

restraining bars, see Figure 6. 

Laser spot welds, one inch apart, were made 

through the face sheet joining it to a parallel set 

of stiffeners. The structure was then rotated by 

901 about an axis perpendicular to the face 

sheet, and a similar set of spot welds was made 

joining the face sheet to the second parallel set of 

stiffeners, which were perpendicular to the first 

set. The panel was then removed from the positioning 

fixture, turned over, and the process was 

repeated. In both the spot welding and the continuous 

welding steps to follow, welding started 

at the innermost stiffener(s) and progressed toward 

the face edges. No distortion of the panel 

was observed after spot welding the face sheets 

to the stiffeners. 

With the spot-welded panel restrained by the restraining 

bars as illustrated in Figure 6, one face 

sheet was then continuously autogenously laser 

welded to a parallel set of stiffeners. After this 

step, the panel was released from the restraining 

bars. When the bars were removed, the tension 

stresses in the face sheet were partially relaxed 

by the distortion; however, this distortion caused 

residual tension stresses to develop in the face 

sheet on the opposite side of the panel. 

In order to make a flat structure, the panel was 

then turned over and elastically deformed by the 

fixtures so that it was again completely flat. It 

was then continuously laser welded to the same 

set of stiffeners on their opposite edge. Flattening 

the panel was critical. If the panel was not 

completely flat before the face sheet on the opposite 

side of the panel was welded, the residual 

stresses introduced by continuously welding the 

first side would not be balanced by the residual 

stresses resulting from welding the second side, 

and the panel would still be distorted to an unacceptable 

degree. 

The panel was then rotated 901 in the x–y plane 

(see Figure 5), restrained by the fixtures, and the 

continuous welding process was repeated on opposite 

sides. If welding was carried out in 

accordance with this procedure, it was found 

that a completely flat panel was produced. 

Figure 7 shows a stainless steel 1 ft 1 ft square 

LASCELL panel (Alloy 316). The stiffeners were 

cut with a carbon dioxide laser from sheet 

0.120 in. thick at a speed of 50 in./min using 

2000 W beam power. A high-velocity N2 gas jet 

y 

x 

Figure 5: LASCELL 

Structure 

Figure 6: Positioning 

Fixture and 

Restraining Bars 

NAVAL ENGINEERS JOURNAL 2010 #4 & 97


Figure 7: Stainless 

Steel LASCELL Panel 

(Inset Shows Autogenous 

Weld, White 

Dots Added to Emphasize 

Weld 

Boundary) 

Figure 8: New Watertight 

Door with 

Strong Backs (Arrows) 

Used to Restrain 

Frame during Welding 

to Bulkhead 

98 & 2010 #4 

was focused concentric to the beam to aid material 

removal. The face sheets were laser cut from 

sheet 0.036 in. thick. 

For the laser welding, a helium cover gas was 

used to suppress plasma formation. At a speed of 

130 in./min and 2000 W beam power, it was 

found that a weld 0.035 in. wide was formed at 

the interface where the stiffener edge was joined 

to the face sheet. 

In developing the process to fabricate LASCELL 

panels, an important and unanticipated feature 

of the laser-welded panels was discovered that 

differentiates them from honeycomb panels 

formed by other methods. If fabricated in accordance 

with the preceding description, these 

panels were prestressed so as to increase their 

resistance to the usual honeycomb panel failure 

mode, localized plastic face sheet buckling. Discussion 

of the mechanics and properties of these 

panels is beyond the scope of this paper, but has 

been presented elsewhere (Copley et al. 2005; 

Copley et al. 2006). 

Adaptation of the LASCELL panel structure to 

the watertight door was first accomplished by 

fabricating a one-half scale door. In this case, restraining 

bars were used and a procedure similar 

to that described for fabricating the 1 ft 1ft 

square panel was followed. In fabricating, a full 

size door, it was found however that the restraining 

bars flexed and were not sufficiently 

stiff to flatten the panel after the initial continuous 

laser welding step. 

A new procedure was devised involving the encasement 

of the door in a massive aluminum 

fixture with slots to allow passage of the laser 

beam. This approach was used to fabricate the 

first full size watertight door of the new design at 

ARL Penn State, and was used as the basis for a 

bid package distributed to 10 potential manufacturers 

deemed capable of manufacturing the 

new door. Five of these responded to the request 

for quote with formal proposals. The two lowest 

bids were selected, and the winners manufactured 

the first set of 10 doors. They were 

Begneaud Manufacturing Inc., Lafayette, LA, 

and MDL Manufacturing Industries Inc., with 

plants in Bedford, PA and White Plains, MD. 

The first 10 doors that were fabricated were used 

for development of the seal system, for a trial 

installation at NGCNN, for precertification 

shock testing, and for display. 

Handling the massive aluminum fixtures used to 

manufacture the first set of watertight doors 

proved to be too time consuming and costly. 

MDL was tasked to develop an automated pro- 


cess for laser welding the watertight doors. They 

developed such a process to manufacture doors 

for precertification hydrostatic testing, certification 

testing, and for two in-service shipboard 

evaluations. 

PLUG-IN-HOLE FRAME INSTALLATION 

Figure 8 shows three aluminum installation fixtures 

(strong backs) developed by NSWCCD to 

restrain the panel of the door during welding of 

the plug-in-hole frame to a bulkhead. This photograph 

was taken at Aeronav Test Labs, 

College Point, NY, before precertification shock 

testing. 

The strong backs were of great value during the 

trial installation carried out by ARL Penn State 

in collaboration with NGCNN and NSWCCD 

at Newport News. During shipboard installation, 

the panel must be removed from the frame 

to provide an escape path in the event of a fire. 

While leaving a path for escape, the strong backs 

provided sufficient restraint of the frame so that 

distortion during welding to the bulkhead was 

kept to an acceptable amount. Furthermore, the 

strong backs provide a means of attaching a 

hoist to lift the door into place during installation. 

The trial installation at NGCNN suggested 

a number of design improvements to facilitate 

shipboard installation, a full discussion of which 

is beyond the scope of this paper. 

HYDRAULICALLY ACTUATED SEAL SYSTEM 

The hydraulically actuated seal system proved to 

be the greatest challenge of the new watertight 

door design. The final design concept is illustrated 

in Figure 9. 

In Figure 9, the gasket (green) is shown in the 

closed door position. It is installed by snapping it 

into place between the containment rods that are 

tack welded to the panel rim as illustrated in 

Figure 10. 

If the door is flooded from the interior side, water 

presses the interior maxi-wiper against the 

frame rim thus blocking flow. The interior containment 

rod is spot welded to the panel rim so 

EXTERIOR SIDE (SIDE WITH HINGES AND LATCHES) 

Exterior Maxi-Wiper 

Exterior Containment Rod 

Exterior Containment Tab 

Exterior Side Mini-Wiper 

Panel Rim 

Interior Mini-Wiper 

Interior Containment Tab 

Interior Containment Rod 

Tack Weld 

Interior Maxi-Wiper 

INTERIOR SIDE 

Tack Weld 

Frame Rim 

water can seep between the rod and the rim and 

may seep under the interior containment tab. 

The purpose of the interior mini-wiper is to 

block such flow. On the other hand, if the door is 

flooded from the exterior side, water is blocked 

by the exterior maxi-wiper pressing against the 

frame rim. Flow seeping under the exterior containment 

rod and containment tab is blocked by 

the exterior mini-wiper. 

The purpose of cavities within the gasket is to 

balance flow during the extrusion manufacturing 

process so that flow through the central 

region of the gasket does not advance too far 

beyond flow in the narrow wipers. 

Current Status 

Much interesting detail regarding the evolution 

of the design of the new watertight door has 

been omitted here in the interest of brevity. The 

following summarizes the current status. 

Gasket 

Exterior 

Containment 

Rod 

Exterior 

Maxi-Wiper 

Panel 

Rim 

Interior 

Containment 

Rod 

Figure 9: Hydraulically 

Actuated Seal 

System 

Figure 10: The Gasket 

Was Installed by 

Insertion between the 

Containment Rods 

NAVAL ENGINEERS JOURNAL 2010 #4 & 99


Figure 11: New 

Watertight Door 

Showing Holes in 

Stiffeners along the 

Neutral Axis Before 

Spot Welding the 

Face Sheet to the 

Stiffeners 

Figure 12: Automated 

Welding 

System Developed by 

MDL under Subcontract 

to ARL Penn 

State 

100 & 2010 #4 

WATERTIGHT DOOR DESIGN 

The stiffener arrangement in the panel and frame 

of the new door is illustrated in Figure 11. Extensive 

finite-element analyses were carried out to 

ensure the structural integrity of the watertight 

door. They resulted in increasing the stiffener 

height to 1.3 in. and the face sheet thickness to 

0.048 in. to increase stiffness and strength. A 

compensating weight reduction was achieved by 

laser cutting holes centered on the neutral axis of 

the stiffeners. 

The new watertight door was hydrostatically 

loaded multiple times during prototype lab testing 

to 15 psi pressure, an overload of 50%, 

without permanent deformation, mechanical 

failure, or any loss of functionality. 

The new watertight door weighed assembly including 

frame 213 lbs, a 27% reduction 

compared with the 26 in. 66 in., 10 psi 

NSWTD. 

SEAL SYSTEM 

Leakage at low rates ( 1–10 mL/min) was not 

difficult to achieve with the hydraulically actuated 

seal system, but the Navy requires zero 

leakage at 10 psi design pressure. Although presenting 

a great challenge, this requirement was 

finally satisfied in laboratory testing. Important 

issues contributing to this success included: controlling 

the gasket length; forming a smooth 

joint between the ends of the extrusion; uniform 

positioning of the gasket in the corners of the 

door; and smoothness of the gasket cavity. ARL 

Penn State worked closely with its supplier, 

Northwest Rubber Extruders, Beaverton, OR, to 

address these issues. 

A hydrostatic loading test matrix specified by 

NSWCCD was successfully completed, including: 

two frame/panel combinations from 

different doors; two different gaskets; and two 

loading directions (repeated three times) giving a 

total of 2 3 3 5 24 successful tests. In each test, 

the door was loaded to 10 psi and held for 20 

minutes with no leaks whatsoever. The opening/ 

closing (pull/push on handle) force for the new 

watertight door was o2 lbs. 

MANUFACTURING 

The automated manufacturing system developed 

by MDL to manufacture the new watertight door 

is shown in Figure 12. The door was attached to a 

rotary stage after spot welding. Several welds 

were made on one side and then the door was rotated 

so that the thermal stresses and distortion 

produced by these welds could be balanced by 

making welds on the opposite side. This was continued 

in a specified weld sequence until the 

welding assembly was completed. In Figure 12, 

the door is shown in mid rotation with five continuous 

welds completed on one side. 

The automated welding system has demonstrated 

the capability of completing all 

continuous autogenous laser welds, approximately 

332 ft of welds, in 45 minutes. This 

automation is critical to achieve the goal to reduce 

the procurement cost to US$4,500 per door 

assembly. 


TESTING 

The new door design has undergone extensive 

precertification testing, and actual US Navy 

Certification tests are just beginning. Perhaps the 

most critical certification test is the Grade A 

shock test in accordance with MIL-S-901D that 

specifies that the door be hydrostatically tested 

to design tightness pressure and function at the 

end of three shock blows. The test is conducted 

in three door orientations: (a) door upright; (b) 

door rotated 451 in plane of the panel; and (c) 

door rotated 451 out of plane. The latter orientation 

is shown in Figure 13. 

The door sits on a platform that is impacted on 

the underside by a heavy swinging pendulum 

hammer. The handle of the door was shortened 

for the test to balance the door latching mechanism 

and eliminate the opening moment. Later, 

this adjustment was incorporated into the design 

by replacing the stainless steel handle with a lightweight 

fiber reinforced composite handle and 

rubber cap. The new watertight door survived 

the shocks without structural damage; however, 

the hydrostatic testing was omitted during precertification 

testing because the seal system had 

not been perfected at the time of the test. 

As previously mentioned the new watertight 

door underwent numerous hydrostatic tests as 

part of the door and seal development and in 

completing NSWCCD’s test matrix. The test 

tank arrangement is shown in Figure 14. The 

frame was welded to a 0.5 in. mock bulkhead. 

The bulkhead was bolted to the tank and sealed 

with an expandable tape gasket. Water was supplied 

to the tank through an inlet pipe visible on 

the right hand side of the tank. Pressure at the 

bottom of the tank was measured with the pressure 

gage. 

One of the doors was successfully hydrostatically 

tested to 10 psi without leakage as the first 

step in the hydro/million cycle open–close, 

latch–unlatch/hydro reliability test required for 

US Navy certification. It has been delivered to 

NSWCCD for the cyclic testing, and is to be followed 

by postcyclic hydrostatic testing. 

CERTIFICATION TESTING 

NSWCCD has taken the lead in arranging and 

conducting certification tests in accordance with 

the American Bureau of Shipping Naval Vessel 

Rules Part 1, Chapter 5, Section 1, Paragraph 

2.4. In addition to hydrostatic, shock and cyclic 

tests, vibration, fire performance, EMI tests, and 

in-service evaluations are required. Technical 

Warrant Holder approval will be based on successful 

completion of the certification tests and 

on successful in-service evaluation described as 

follows. 

Figure 13: Shock 

Test of New Watertight 

Door Rotated 

451 Out of Plane 

Figure 14: New 

Watertight Door 

Welded to Bulkhead 

That Bolted to Hydro- 

Test Tank 



102 & 2010 #4 

IN-SERVICE EVALUATION 

Two at-sea, in-service evaluations are planned 

for initiation in FY 2010 and will require 1 year 

to complete. Six additional at-sea, in-service 

evaluations involving three platforms, two doors 

each, are planned and are anticipated to be completed 

by early CY 2012. In these evaluations, 

the doors will be retrofitted onto actual ships and 

subjected to typical US Navy in-service use. 

SummaryandConclusions 

& A new watertight door based on laser cutting 

and welding technology has been designed, 

manufactured, and tested, offering reduced 

weight and reduced total ownership cost 

compared with the NSWTD. 

& Novel features of the new door include its 

LASCELL panel structure, plug-in-hole frame, 

and hydraulically actuated seal system. 

& Assuming success in all US Navy certification 

testing and NAVSEA technical warrant holder 

approval, this new door design will offer an 

attractive choice for insertion by Acquisition 

Program Managers and Fleet Maintenance 

Managers. 

Acknowledgments 

The authors are grateful to their colleagues 

James Burton, David Simunov, Ernesto DiSandro, 

Kenneth DiFonzo, Constantine Pappas, and 

John Tareila at the Naval Surface Warfare Center 

Carderock Division—Ship Systems 

Engineering Station, Philadelphia, and David 

Rice and Anna Yurashus at Northrop Grumman 

Corporation, Newport News, for their technical 

contributions and interest. They would like to 

thank the staff at the ARL Laser Processing Division 

Laboratory, especially Chris Sills for his 

assistance in the early phases of the project, and 

Richard Martukanitz for his role in identifying 

the opportunity for laser technology to address 

the need for an improved watertight door. They 

would also like to thank Tim Bair, iMAST Director; 

and John Carney, Director; and Greg 

Woods, Program Officer, of ONR ManTech as 

well as Glen Sturtevant, Director of Science & 

Technology, PEO Ships, and William Boulay, 

American Systems Inc.; for their continuous interest 

and support. 

This material is based upon work supported by 

the Office of Naval Research, through the Naval 

Sea Systems Command under Contract no. 

N00024-02-D-6604. Swampworks funding and 

Technology Insertion Program for Savings funding 

are gratefully acknowledged. 

Any opinions, findings, conclusions, or recommendations 

expressed in these materials are 

those of the authors and do not necessarily reflect 

views of the US Navy. 

References 

Burton, J. and D. Simunov, ‘‘In-service surface ship watertight 

doors: analysis of options,’’ Presented to PEO 

Ships F Program Reviews, Watertight Door Technical 

Splinter Group, February 15, 2006. 

Copley, S.M., E. Ventsel, and P. Vigna, ‘‘Laser fabricated 

metallic cellular sandwich panels,’’ Proceedings of the 

International Congress on Applications of Lasers and 

Electro Optics, ICALEO’05, Miami, FL, November 3, 

2005. 

Copley, S.M., P. Vigna, and E. Ventsel, ‘‘Beneficial prestress 

in laser fabricated, metallic, square, cellular 

sandwich panels,’’ Proceedings of the International 

Congress on Applications of Lasers and Electro Optics, 

ICALEO’06, Scottsdale, AZ, October 30, 2006. 

NAVSEA, NAVSEA STD DWG 803-2226372 Rev B, doors, 

hatches, and scuttles—general notes, October 6, 1987. 

AuthorBiographies 

Stephen M. Copley is the principal author. He is 

Senior Scientist at the Applied Research Laboratory, 

Materials and Manufacturing Office, 

Laser Processing Division, and Professor of Mechanical 

Engineering, Penn State University. Dr. 

Copley received his B.A. in Physics, M.S., and 

Ph.D. in Engineering Science, all from the University 

of California at Berkeley. A technical 

contributor to the laser materials processing 

field since the 1970s, he is a Fellow of ASM 

International and ASME; e-mail: smc21@ 

psu.edu. 


Edward W. (Ted) Reutzel is the Head of the System 

Engineering and Integration Department 

within the Laser Processing Division at the 

Applied Research Laboratory, Penn State University 

(ARL Penn State). He has 15 years of 

experience in welding, modeling, sensing, control, 

and laser processing. Dr. Reutzel received 

his B.S. in Mechanical Engineering from the 

Georgia Institute of Technology and his Ph.D. in 

Mechanical Engineering from Penn State 

University. 

Terri A. Merdes is a test engineer and finite-element 

analyst in the Advanced Computational 

Analysis and Design Department, Composite 

Materials Division at the Applied Research 

Laboratory, Penn State University. She received 

her B.S. in Mechanical Engineering and her M.S. 

in Quality Manufacturing and Management 

from Penn State University. 

Dennis B. Wess is a mechanical design and analysis 

engineer in the Process and Product 

Development Division at the Applied Research 

Laboratory, Penn State University. He received 

his B.S. and M.S. in Mechanical Engineering 

with a minor in Engineering Mechanics from 

Penn State University.

Design, Manufacturing, and Testing of an Improved Watertight Door ...

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