Stachiw 



Recently, materials like glass and ceramics have been dis- 

 covered! > 2 to possess such high compressive strength, modulus of 

 elasticity, and resistance to corrosion that buoyant deep submer- 

 gence hulls for fixed or mobile installations can be built for any 

 depth. Unfortunately, although glass and ceramics have the potential 

 of providing man with hulls of ultimate depth capability, the engi- 

 neering problems to be solved are formidable, and the materials are 

 too expensive for applications in shallow depths where their use is 

 not mandatory. Since currently available glass and ceramic materi- 

 als with the ultimate depth capability have been found impractical 

 for general use because of their high costs of fabrication and yet 

 unsolved joint design problems, the path has been cleared for other 

 materials with limited depth capabilities, but with an attractive 

 cost factor and ease of applicability to large structures. Such a 

 material is concrete which is theoretically satisfactory for buoy- 

 ant hulls with an operational depth requirement of 3,000 to 4,000 

 feet. In addition, engineering estimates indicate that it is more 

 economical than other available metallic or nonmetallic materials 

 when used in large ocean bottom habitat structures. 



The depth capability of 3,000 to 4,000 feet of buoyant concrete 

 structures which can be towed to location and submerged, permits 

 the utilization of such structures over large areas of the conti- 

 nental borderlands. About 127o to 14% of the ocean floor can be 

 explored and settled using concrete as the primary hull construction 

 material for the ocean floor installations. While the portion of 

 ocean floor that could be made accessible through the use of con- 

 crete hulls is small in comparison to the total ocean area, in 

 terms of importance, it is a most critical part of the total. The 

 reason for its importance is found in the presence of large con- 

 tinental borderlands made up of shelves, and submerged banks in zero 

 to 3,500 foot depth range. Since these shelves and banks are 

 generally flat to gently sloping, and since they are also in the 

 general vicinity of land, they make ideal construction sites. 



The areas of primary interest to the United States are direct- 

 ly accessible from this country without transversing ocean floors 

 that are under another country's sovereignty. By occupying the 

 shelves and banks adjacent to the United States in the 0- to 3,500- 

 foot depth range, the land area of the United States could be ex- 

 tended approximately 2370. 



In summary, it can be stated that although there is a need to 

 develop materials and structures with ultimate depth capability, 

 development of materials and structures for depths to 3,500 feet 

 is more important in terms of national defense and natural resources. 

 Since concrete has been in many cases the most economical construc- 

 tion material on land, it should be investigated early in the 

 search for undersea construction materials. It may also turn out 

 to be one of the most economical materials for ocean-floor con- 

 struction on continental shelves and submarine banks in the to 

 3,500-foot depth range. 



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