273 



Trieste, designed by August i'iccard ; but veliicics like tlie Trieste and its Frent-li 

 counterpart, Archimede, Iiave serious limitations for commei-cial use: they re- 

 quire surface support; the use of aviation petrol for buoyancy is a hazard that 

 limits the sea conditions in which they c-au successfully operate and they are 

 un wieldly for engineering operations. Thus increasingly advanced vessels derived 

 either from the precision-controlled, welded pressure hull have been or are being 

 built not only for ocean engineering but also for scientitic, tourist, rescue and 

 military purposes. Some of these vessels, which do not require surface tenders, 

 like bathyscaphs already have near bottom capability exceeding 2000 metres for 

 extended periods of time. While further progress in the construction of the types 

 of vessels described is possible, it is believed that if present materials — high 

 strength steels and aluminum — continue to be used, rapidly increasing costs 

 would inhibit extensive commercial and military intrusion into the deep sea. It 

 appears, however, that we are close to a vital breakthrough in technology. 



In a paper presented at the Conference on Law, Organization and Security in 

 the Use of the Ocean held at Ohio State University in March this year. Dr. 

 Craven stated : 



"It has also been suggested by many that the problem of ocean-mining is 

 remote and that exploiters will be relatively few. The presumption is the pro- 

 jected high cost of vehicles and equipment operating on the ocean bottom. It 

 is the thesis of the author that low cost vehicles capable of exploitation are 

 technologically feasible and will be realized within the next decade. This projec- 

 tion is based on three fundamental premises : one, that deep submersibles . . . 

 will operate independently of the free surface ; two, that materials for deep sub- 

 mergence will ultimately be less expensive than materials now in use for rela- 

 tively shallow submersibles ; and three, that free-flooded deep machinery will 

 have been developed. It is surprising to the uninitiated and even to some profes- 

 sionals ... to realize that at present the major investment cost of deep sub- 

 mersibles is in the surface ships and surface support . . . This is so, because, 

 except for static pressure, the greatest forces and most dangerous dynamics are 

 at or near the surface and its attendant wave systems. . . . The resulting elimina- 

 tion of surface support will provide the greatest cost reduction in the system 

 operation. 



"The second greatest potential is in materials for deep submergence. Much 

 has been said in the past about the promise of glass and ceramics for use as a 

 low-cost hull material. . . . Perceptible progress has been made." (Volume II, 

 pp. 17-18) 



"The third aspect is the development of freeflooding machinery capable of 

 operating in the deep sea. Such equipment has indeed been built and employed. 

 ... A costly development programme should see a commercially available ca- 

 pability for tethered, unmanned vehicles or even tethered, manned vehicles ca- 

 pable of exploiting the deep sea in the near future." (Volume II. p. 19) 



In a further paper published in the Proceedings of the U.S. Naval Institute 

 in April 1966 Dr. Craven described at some length the advantages of using 

 massive glass pressure hulls. I shall not go into technical details. All I say in 

 this respect is that deep submergence vehicles, utilizing these new techniques, 

 are now under construction ; they will be capable of operating at depths ex- 

 ceeding 700 metres for prolonged periods. They will come into operation within 

 the next two years. 



A second major technological development which is making the sea-bed 

 accessible and exploitable resides in the adaptation of the physiology of man 

 to permit him to operate freely in the ocean at depths at least as great as those 

 of the geophysical continental shelf. The major innovation here is the applica- 

 tion of the technique of saturation diving. In this technique, the diver is com- 

 pressed in an artificial atmosphere (usually oxygen, nitrogen and helium) appro- 

 priate to the depth at which he is to operate until the gasses dissolved in his 

 body fluids and body tissues are at an equilibrium. Once appropriately saturated 

 the diver may make limited excursion to deeper depths but may not safely 

 enter shallower water without long and careful decompression. It has been 

 observed that from the surface an excursion to 70 metres is near the maximum ; 

 from 70 metres to 150 metres is more easily tolerated ; from 150 metres excur- 

 sions up to 300 metres — well beyond the geophysical continental shelf isobath — 

 appear to be permitted. The ability to do protracted work on the sea-bed re- 

 quires the technological capability to heat the diver while he is in the water and 

 a dry chamber which can be occupied during non-working hours. The Conshelf 

 and Sea Lab I and II experiments have demonstrated that this capability exists 



