HYDRODYNAMIC ASPECTS OF A DEEP-DIVING 
OCEANOGRAPHIC SUBMARINE 
P. Mandel 
Massachusetts Institute of Technology 
INTRODUCTION 
There is little question that the major problems that arise in the design of very deep 
diving submarines are in the field of structures and not in the field of hydrodynamics. How- 
ever, several hydrodynamic problems exist that are peculiar to the very deep diving oceano- 
graphic submarines that are of little or no importance in the design of the most advanced 
military submarines. These problems arise in connection with: (a) the ballast systems 
needed for operation at great depths, (b) the oscillations that may be excited by vortex 
shedding during vertical ascent or descent, (c) the effects on depth and trim angle control 
of the compressibility of the submarine hull and of sea water, (d) the precise control in 
both the horizontal and vertical planes needed to perform the mission of the boat, and 
(e) directional stability when under tow on the surface. This paper will concern itself 
largely with these five questions plus some introductory discussion of how the configura- 
‘tion of a deep-diving submarine compares to military submarines and bodies of revolution 
of elementary shape. - 
This paper will draw on experience gained during the design of the oceanographic sub- 
marine Aluminaut which is described in Ref. 1. The design of this unique vehicle was 
based on general concepts initiated by Dr. Edward Wenk, formerly of Southwest Research 
Institute, San Antonio, Texas. The design was developed to its current state under a 
project initiated by Mr. J. Louis Reynolds, Vice President, Reynolds Metals Company. 
Negotiations for construction of the boat are currently nearing completion. 
The Aluminaut differs in basic concept from the previous generation of deep-diving 
vehicles marked by the bathyscaphes FRNS and Trieste which were developed by Auguste 
Piccard. It will be recalled that it was the Trieste which made the record-breaking dive on 
January 22, 1960, to a depth of 37,800 feet. These vehicles depend on a buoyant liquid, 
gasoline, to support about 90 percent of their total weight while their small pressure hulls 
support only about 5 percent of their total weight. The remainder of their weight is sup- 
ported by the buoyancy of structure. In contrast the buoyancy of the pressure hull of the 
Aluminaut supports over 80 percent of its total weight. The marked effect of this change of 
concept can be seen by study of Table 1. With a total submerged displacement of slightly 
more than half of the Trieste, the Aluminaut has about 9-1/2 times the useful volume and 
possesses mobility and endurance that are vastly superior to the Trieste. It is these defi- 
ciencies of the Trieste plus the difficulties in handling large quantities of volatile gaso- 
line that prevent full appreciation in oceanographic research work of her superlative depth 
capability. Even the retrogress of the Aluminaut from the remarkable depth capability of 
the Trieste is more apparent than real since only about 40 percent of the world’s ocean area 
is greater than 15,000 feet deep. Thus, the Aluminaut has great potentiality as an oceano- 
graphic research vehicle. - 
307 
