Ocean Engineering 



During the past year, long-standing Navy programs of material develop- 

 ment reached fruition in four areas: 



— heat-treatable steel with a yield strength of 130,000 to 140,000 p.s.i. 

 was approved for use on Deep Submergence Rescue Vehicles and 

 other manned submersible hulls (previously approved limit was 



100,000 p.s.i.); 

 — laboratory tests proved that one alloy of titanium can be used in 

 salt water without cracking due to stress corrosion (earlier there 

 were indications that alloys of this material with a high strength to 

 low density ratio could not be used in salt water) ; 

 — alloys of nickel and copper with considerably increased strength were 



developed for use in submarine piping systems ; 

 — non-destructive test methods and criteria were developed for evaluat- 

 ing low-density syntactic foams which are used to supplement the 

 buoyancy of underwater vehicles. 

 Additional milestones in FY 1968 include modifications of the Navy's 

 Cable-controlled Underwater Recovery Vehicle (CURV II) for enhanced 

 reliability to depths of 2,500 feet and starting construction of CURV III for 

 an operating depth of 7,000 feet. 



Advancements were reported in the technology for designing, construct- 

 ing, and operating fixed and semi-fixed habitats in which men can live and 

 work deep in the ocean at atmospheric pressure. Such structures, which may 

 be either on or in the sea bottom, have potential application for military 

 missions and also for civilian tasks of permanent or semi-permanent nature 

 such as mining. In FY 1969, this program will emphasize investigation of: 

 — hollow concrete cylinders for pressure-resisting structures at great 



depths ; 

 — behavior and nature of sea floor sediments ; 

 — corrosion and biological fouling ; 



— surveying techniques for precise determination of relative location of 

 bottom and surface points. 



Power for Underwater Tasks 



Perhaps the most critical, unmet need of underwater technology is for 

 inexpensive power sources with longer endurance. Today nearly all under- 

 water missions, except for military nuclear submarines, are limited by the 

 low capacities of available batteries. Advances are thus being sought to 

 increase the energy available per pound, per cubic foot, and per dollar of 



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