Deep-Diving Submarine Hydrodynamics 333 
Characterization 
Description of Behavior : 
a as Pai ld of Behavior 
4. The model would remain in a stable Satisfactory 
equilibrium position throughout the 
run. 
Tests with the small stern fins yielded the following results: 
Towing Characterization 
: Comments 
Arrangement of Behavior aan 
(a) Unsatisfactory 
(b) Satisfactory Equilibrium position 
slightly to port of 
initial position 
(c) Satisfactory Equilibrium position 
slightly to port of 
initial position 
(d) Satisfactory 
Similar results were obtained with the large stern fin tests except that with towing 
arrangements (b) and (c) the model veered more to port and the equilibrium position was 
further to port. In order to help ascertain the cause of this distinct bias, configurations (b) 
and (c) were tried with the model set initially heading to starboard. The model still turned 
to port and established a stable equilibrium position on the port side of its initial position. 
Subsequently, the model was also tested with the stern fins removed entirely. In this condi- 
tion, towing arrangements (b) and (c) became unstable, although no bias either to port or 
starboard was evident. It was concluded from these tests that both the original and enlarged 
rudders were not set exactly parallel to the center line of the model, and that the bias to 
port which was even more evident with the enlarged rudders was due to the inaccurate initial 
setting of the rudders. 
Application to Full-Scale Towing 
The model results indicate that towing arrangements (b) and (c), or (d), would be satis- 
factory for the full scale. From a practical point of view, (c) or (d) appear preferable to (b) 
which involves the fitting of a large spanner subjected to very heavy cantilevered loads. 
The bias that the model possessed for the port side is considered of little consequence 
since the zero position of the full-scale rudders can be easily adjusted. It was concluded 
from the tests that satisfactory towing of the Aluminaut on the surface could be accomplished 
with at least two simple towing arrangements. 
SUMMARY OF PAPER 
The contrasts between the Aluminaut and both the previous generations of deep-diving 
vehicles and conventional military submarines are emphasized in this paper. In the field 
of hydrodynamics, special problems arise with deep-diving submarines that require different 
ballasting systems as well as different devices for effecting superior control at low speeds. 
646551 O—62—_23 
