for the SEACLIFF or TURTLE vehicle. The hull is scheduled for 

 completion and installation early in FY 71. When completed, and 

 with other modifications to the vehicle, this hull will provide a 

 12, 000 foot operating depth capability with a 2, 300 pound payload. 

 Also, this type of titanium will be qualified as a Class I material 

 for small structures. With the present HY-100 steel hulls the 

 SEACLIFF and TURTLE vehicles have a 6, 500' operating depth 

 and approximately a 350 pound payload. 



In the area of non-metals, development should continue in 

 structural glass, fiber reinforced plastics, acrylics, ceramics, 

 syntactic foam and concrete. These materials have been identified 

 within the Navy and by the NAE and the Marine Council as having 

 an important role in ocean engineering. Of all the non-metals 

 considered, glass is the one material where there is an abundance 

 of claims but a conspicuous lack of available technical infornnation. 

 Fabrication, joining techniques, and non- destructive test proce- 

 dures do not yet permit reliable exploitation of the theoretically 

 achievable strength obtainable with glass. To date, the Navy's 

 program in glass has been splintered and fragmented. Efforts 

 are being formulated for a comprehensive program in development 

 of structural glass. We are only at the point of investigating the 

 chemical, physical and mechanical properties of glass. Estab- 

 lishment of specifications, fabrication technology, and non- 

 destructive test methods and standards are later objectives. The 

 end goal is a certified manned glass pressure-hull for 20, 000' 

 within 8 years at a total estimated program cost of $16 million. 



Concrete, long used for ocean surface and near surface in- 

 stallations in and around harbors, is an interesting candidate 

 material for future deep water work such as mobile and fixed 

 underwater stations. Ease of fabrication and low cost make con- 

 crete attractive as a primary building material for ocean bottom 

 installations at the continental shelf depth levels of 600' . It has 

 not, however, been properly investigated for these new ocean 

 applications and therefore requires considerable development. 



Today's buoyancy material provides too little buoyancy (about 

 1/2 pound per pound of material) and its resistance to high pres- 

 sures is not satisfactory. State-of-the-art syntactic foam weighs 

 42 Ibs/ffS for a 20, 000 ft. application. We need 34 Ib/ffS foam or 

 less to keep vehicle size within reasonable limits and to provide 

 an increased payload capability. 



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