Analysis Used in Submerged Body Research 429 
MEANDER 
Fig. 40. Typical meander and 
vertical overshoot maneuvers 
(definitive maneuvers) 
Rate of Change 
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re 
ole 
Se 
@ 
Cir 
@ 
slo 
a 
Rudder Angle 
Rudder Angle 
(a) Stable ship (b) Unstable ship 
Fig. 41. Typical curves from spiral maneuvers 
relative to a grid attached to the towing carriage, using cameras mounted inside the model. 
The main objections to this system are that it required an expensive model and that the ex- 
cessive drag resistance of the tubing affected the maneuvering characteristics of the model. 
With recent advances in electronic and electromechanical instrumentation, and water- 
proofing techniques, it became possible to perfect the free-running model technique using 
the standard 20-foot (nominal) submerged models used for both resistance and propulsion 
tests and stability and control tests. 
The free-running submarine model tests are presently being performed in the J-basin at 
DTMB. Techniques have been developed so that these tests can be conducted in the new 
Maneuvering Basin using a model that is internally programmed and has internal recording 
equipment. 
646551 O—62:——_29 
