Stewart and Poudrier 



point of 281 degrees for potting. Tliis low temperature does not 

 damage the electrical insulation, and the terminator will hold the full 

 breaking strength of the cable. In order to control the point at which 

 the cable parts, a cutter blade is incorporated in the terminator. This 

 may also serve to prevent damage to the meter wheel. 



A smaller version of this device has been developed for use with the 

 mechanical bathythermograph or other small instruments lowered on a 

 solid wire of similar diameter. With this device no attempt is made 

 to cut the cable, and the terminator is replaced with a swaged fitting 

 of the type used on aircraft control cables. Tlie ultimate goal of 

 design simplicity has almost been reached here -- there is only one 

 moving part. Preliminary tests results in the laboratory have proven 

 completely successful, but more testing will be conducted before it 

 will be considered ready for field installation. In view of the 

 large number of Navy ships using mechanical BT's, the potential savings 

 which could result from such a simple device are quite large. 



Tlie next item to be described is a recovery system for a towed acoustic 

 transducer housing. The office has lost towed transducers used in 

 geophysical survey operations. Cost of the transducer and housing is 

 approximately $30,000 and a lead time of about four months required 

 to replace a lost unit. The complete unit is nine feet long, weighs 

 2000 pounds in air and 800 pounds in water. It is normally towed 

 continuously by the survey ship at a depth of about 100 feet. Failures 

 had occurred in the terminator, the cable, and the point of attachment 

 to the structure of the housing. The recovery system developed 

 borrowed heavily from techniques used in recovery of exercise torpedoes. 

 Compressed air cylinders were mounted within the body of the fish, and 

 inflatable flotation bags mounted behind doors cut in the housing. In 

 operation, if the "fish" drops below a preset depth an actuator 

 mechanism opens an air valve from the bottles, an air solenoid unlatches 

 the doors, and the flotation bags are deployed and inflated. At the 

 same time an independent system actuates a Xenon flasher on the tail 

 fin of the "fish" and an acoustic pinger on the bow to aid in location. 

 This system has been field tested and performed satisfactorily. 



With this system we needed an actuating device which would be reliable 

 in operation, have long shelf life, and require a minimum amount of 

 attention by the shipboard personnel. The solution, which is shown 

 in the slide, consists of a cylinder having at one end a rupture disc 

 set to break at the proper depth. When the disc breaks a compartment 

 containing a sea-water battery is flooded and the battery energized. 

 This in turn fires an explosive squib, which drives a piston to open 

 the air valve. Operation of the piston is obtained in 0.6 seconds 

 after rupture of the disc. We feel that this has been a worth while 

 project, since several of these transducer housings are in constant use 

 in the Marine Geophysical Survey program. It is not, however, of very 

 general application, since it was designed for one particular instru- 

 ment housing to be used in a given manner. Our attention now has 

 turned to systems having a broader potential use with a variety of 



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