ABSTRACT 



The feasibility of fabricating a deep -submergence 

 pressure hull composed of rings joined by means other than 

 welding was explored in tests of three structural models 

 (two of aluminum and one of titanium) designed for a 

 collapse strength of 10,000 psi. These tests demonstrated 

 that hulls can be built without welding and that these 

 hulls can have collapse strengths comparable to monolithic 

 hulls. Longitudinal strength, watertight integrity, and 

 corrosion protection, which were not explored by these 

 tests, can be provided by any of several mechanical 

 techniques without compromising collapse strength. 



INTRODUCTION 



Growing interest in the ocean depths both in scientific and military 

 circles has emphasized the need for vehicles capable of operating at great 

 depths. It is recognized that the materials and the fabrication techniques 

 now in use place a severe limitation on the size and maximum operating 

 depth of positively buoyant vehicles. Much interest has been shown in 

 using light, high-strength materials such as aluminum, titanium, glass- 

 reinforced plastics, and high-strength steels. Solid glass is also being 

 investigated. 



The most difficult problem in utilizing these new materials is that 

 very few of them can be welded and still retain their strength character- 

 istics. In addition, the thick sections required for larger diameter hulls 

 make welding extremely difficult and expensive even where it is possible. 



Techniques have been proposed for eliminating or reducing the 



welding problem where large rings are used to form the strength elements 



of the cylindrical pressure hull. Reynolds proposed a hull of aluminum 



rings held together with tension rods and covered with a thin coating of 



pure aluminum for corrosion protection. The latest design of the ALUMINAUT 



2 

 pressure hull cylinder is composed of rings held together by bolts. The 



David Taylor Model Basin is currently investigating composite-type con- 

 struction in which the strength rings are secured and protected by a thin 



3 

 outer jacket of weldable or otherwise easily fabricated material. 



References are listed on page 10. 



