23. BATHYSCAPHS AND OTHER DEEP SUBMERSIBLES FOR 

 OCEANOGRAPHIC RESEARCH 



R. S. Dietz 



1. Introduction 



There are many types of devices and submersibles for penetrating the sea's 

 third dimension. In order to circumscribe the subject for the purpose of this 

 chapter, the writer proposes to consider here only those capable of descending 

 to considerable depths and designed primarily for oceanographic research. 

 This, at the outset, eliminates from mention military submarines, for example, 

 although considerable oceanography has been accomplished by some of these. 

 The arctic under-ice voyages of the S.S.N. Nautilus and S.S.N. Skate, provide 

 remarkable examples. 



The relative word "deep" can, of course, be construed in many ways as 

 applied to submersibles. In its shallowest sense, it could refer to the working 

 depths attained by unprotected divers. But to study deep mid- water life in situ 

 one must descend below the "twilight zone" — or roughly below 800 m — where 

 animals show strong photic response. To study the sea floor deeper than the 

 fringing continental shelves (7% of the sea bed), a plunge of only 120 m is 

 required; but only another 15% of the sea floor lies between the shelves and 

 3000 m. The average depth of the sea is 3800 m. For generally exploring the 

 abyssal ocean floor (outside of the hadal trench depths which comprise only 

 1% of the sea floor between 6000 m and 11,000 m) one needs a craft with a 

 6000-m capability. 



Marine scientists recognize that the classical methods of data collection with 

 instruments lowered on ropes and wires fall far short of the needs of modern 

 oceanography. In the past decade, geophysical methods using acoustics, 

 magnetics, gravity, etc. have revolutionized concepts of the ocean. In all 

 likelihood, the next break-through will be ushered in by manned invasion of 

 the sea with deep-research vehicles. Prototypes have already been successful 

 and the development of sophisticated crafts is gaining impetus. 



The oceanographer must use his senses in combination with understanding 

 and intuition to unravel the nature of the deep ocean. As well as to measure, 

 he needs to touch, smell and hear ; and most of all to see. This he can do only 

 bluntly through any remote extension of his senses into the abyss by instru- 

 ments. Devices and tools lowered on long wires often have discrimination and 

 precision but they cannot integrate the overall environment. Close-at-hand 

 seeing is especially vital in the largely observational sciences of biology and 

 geology ; less so in marine chemistry and physics. From a deep ship, the eco- 

 logist can survey the animals of mid-water space and study their behavioral 

 patterns. The biologist's use of nets from ships has been aptly compared to a 

 blind man making a butterfly collection. In a classic experiment, Helland- 

 Hansen exposed a photographic plate at the end of a 1000-m wire for 80 min ; 

 he found blackening. This finding was duly reported and textbooks for several 



[MS received September, 1960] 497 



17— s. ii 



