propel, maneuver and control submersibles 

 is reviewed. No attempt is made to catego- 

 rize the various approaches, because the ex- 

 treme variation from vehicle-to-vehicle de- 

 fies classification. 



There is one general statement regarding 

 submersible propulsion which can be made: 

 They are all slow and they all use electric 

 power. Although it may be satisfying in a 

 literary sense, no submersible "darts about" 

 or "speeds off on its appointed rounds. As 

 Cousteau so aptly stated in The Living Sea, 

 "Speed is the enemy of observation." This 

 philosophy has been adopted by submersible 

 designers. Averaging the cruising speed of 80 

 submersibles produces a value of 1.5 knots, 

 with a range from 0.2 knot {FNRS-2) to 6 

 knots (AIGUSTE PICCARD). One and a half 

 knots is equivalent to a casual stroll, and 

 this has been quite acceptable to the under- 

 sea scientist and engineer. The only need for 

 higher speed appears to be on the part of the 

 pelagic fisheries' biologist who desires to ob- 

 serve the migration and behavior of fast 

 swimming fish, such as tuna. To this end 

 General Dynamics conducted a feasibility 

 and conceptual design study of a research 

 submarine for the Department of Interior's 

 Bureau of Commercial Fisheries (now the 

 National Marine Fisheries Service) and rec- 

 ommended a maximum submerged speed of 

 20 knots. Nothing further has evolved from 

 this study, which was completed in 196.5 (1). 



In the submersible field the term maneu- 

 verability has a variety of meanings; it re- 

 fers, not only to the vehicle's ability to twist 

 or turn, but also implies its ability to climb, 

 hover and poke around in close quarters. The 

 requirements for maneuvering at times can 

 be quite severe — on a surveying mission, for 

 example, where ascent (at a constant height 

 of 10-.30 feet above the bottom) from several 

 thousand feet deep to a hundred feet or less 

 may be required. The submersible must be 

 able to "fly" horizontally, then assume an 

 up-bow angle of 30 or more degrees and 

 finally ascend vertically while maintaining a 

 position some 2 or 3 feet away from the face 

 of a vertical escarpment. Such requirements 

 are not hypothetical; ALUMINAUT con- 

 fronted just this problem while bottom sur- 

 veying off Vieques Island, Puerto Rico and 

 St. Croix, U.S. Virgin Islands, in 1967 and 



1968. ALVIIK confronted similar problems in 

 the Tongue of the Ocean, Bahamas in 1966 

 and 1967. These are but a few examples. 

 Other submersibles faced and continue to 

 face equally taxing demands on their maneu- 

 verability and control. The problem is not too 

 different from those of a helicopter. While 

 ocean bottom currents do not nearly ap- 

 proach the wind speeds encountered by a 

 helicopter, submersible power plants are so 

 much less than a helicopter's that the prob- 

 lems are quite comparable. 



The topics of marine propulsion and hydro- 

 dynamics are subjects which comprise books 

 in themselves. Their terminology and princi- 

 ples are multitudinous and complex. Herein, 

 discussion is confined to the minimum of 

 terms and principles needed to describe the 

 motions of a submersible and the devices and 

 physical phenomena which propel and direct 

 it through the water. In the event that a 

 more thorough or technical treatise is de- 

 sired, the following are recommended: 



a) '■''Marine Propulsion'" (2): A historical 

 and semi-technical presentation which 

 describes and illustrates the develop- 

 ment of marine propulsion throughout 

 the ages. 



b) ^'Stability and Motion Control of 

 Ocean Vehicles'" (3): A very thorough 

 and highly technical discussion of the 

 hydrodynamic principles involved in de- 

 signing vehicles and systems and deter- 

 mining their response to the environ- 

 ment. This publication was written as a 

 "partial" text on the subject of motion 

 and control of ocean vehicles offered by 

 the Department of Naval Architecture 

 and Marine Engineering at the Massa- 

 chusetts Institute of Technology. 



c) '"l\aval Hydrodynamics": A series of 

 seven publications from 1957 through 

 1968 presenting the reports of interna- 

 tional scientists and engineers regard- 

 ing marine propulsion, cavitation, noise, 

 hydroelasticity, motions, drag and other 

 aspects of marine propulsion. The con- 

 tents of these books are quite technical, 

 comprehensive and far ranging. A list- 

 ing of the books and their contents can 

 be obtained from the National Technical 

 Information Service, Operations Divi- 

 sion, Springfield, Virginia 22151. 



3 70 



