INTRODUCTION 

 Statement of the Problem 



The Navy deep-submergence effort requires well-equipped deep-ocean 

 simulation test facilities with pressure vessels of sufficient size to accommo- 

 date at least the largest single component of any deep-submergence vehicle or 

 habitat. This represents only the minimum requirement, while a more desirable 

 requirement would be to be able to test any full-size deep-submergence vehicle 

 or habitat to its design depth in a pressure vessel, so that the whole system 

 receives a thorough proof test. 



The current Navy's research and development program requires pressure 

 vessels with an operational capability of 13,500 psi and at least 120 inches in 

 inside diameter and 360 inches in internal length. Such a pressure vessel could 

 test to collapse the structure of an average-sized construction vehicle, or scale 

 model of a habitat to the limit of its 1.5 safety factor for a 20, 000- foot depth. 

 But the size of the above-mentioned pressure vessel is not the ultimate in 

 projected pressure vessel requirements. Larger pressure vessels will be required 

 as the size of the deep-submergence manned vehicle and habitat hulls increases. 

 In addition, more emphasis will be placed on proof-testing complete deep- 

 submergence vehicle and habitat systems in controlled laboratory environment 

 rather than in the ocean environment, where even the slightest malfunctioning 

 of a system component spells irretrievable loss of the vehicle or habitat and of 

 its crew. 



To meet these future pressure vessel requirements, the exploratory 

 hydrostatic pressure vessel study was conducted by NCEL under NAVFAC 

 sponsorship. Its results are presented in this report. 



Background Information 



As indicated in Appendix A, traditional construction techniques are 

 hard put to satisfy the operational requirements of the new generation of 

 pressure vessels that are not only much larger in diameter, but also operate 

 at higher pressures than earlier pressure vessels. For many years prior to the 

 invention and successful use of the multilayer construction technique the 

 single-wall welded or forged monolithic construction of pressure vessels was 



