Fig. 11.12 Magnetometer sensor and glass float on BEN FRANKLIN An explosive 



guillotine device served to cut the 150 ft ot cable m the event of an emergency. 



(NAVOCEANO) 



was used aboard DEEPSTAR 4000 (13), AL- 



VIN (14) and others to obtain average devia- 

 tions from station to station. In the second 

 case, an Askania gravity meter (Fig. 11.13) 

 was used aboard ALUMINAUT and a La 

 Coste & Romberg meter aboard BE1\ 

 FRANKLIN. A comprehensive and detailed 

 report of the techniques and merits of con- 

 ducting gravity measurements from sub- 

 mersibles is presented in reference (15). 



Operation: The gravity sensor is sus- 

 pended in a gimbal and allowed to hang 

 level. It consists of a mass which is a damped 

 hinged beam, a spring with adjustable ten- 

 sion and a photo-cell to measure the beam's 

 motion. Variations in gravity upset the bal- 

 ance of the set spring tension and weighted 

 beam. The resultant motion is caused by 

 change in spring tension, which has been 

 calibrated to indicate a change in gravity. 



Fig 1113 Underway gravity measurements were taken with this Askania gravity meter aboard ALUMtNAUJ (NAVOCEANO) 



553 



