doors by which it was held at the base of the 
launch frame. 
After the drop, the tail section was re- 
covered and the recovery line secured to a winch. 
The missile was then pulled back up into its 
launching frame. The doors holding the missile 
were then shut and made safe by the insertion of 
a pin in the toggle clamp. The entire launch 
frame and missile were then lifted to the deck 
level, secured, and readied for the next drop. 
CONCLUSIONS 
The results of tests conducted by the Acous- 
tics and Seismics Laboratory indicated that the 
experimental approach using a free-falling vehicle 
was sound and that this type of instrument could 
be valuable in acquiring information to increase 
the present knowledge of the physics of hydro- 
dynamic-flow noise. 
This work was supported by the DIMB and a 
contract administered by the Office of Naval 
Research, 
20 
