E-8 

 remove some of the vessel's heave and roll. 



In standard configuration the sled is equipped with: 



1. one high capacity 35 mm camera (400' film reel) ; 



2. one 250 watts/sec. strobe; 



3. one logic package (responsible for electronic 

 timing, sychronization and distribution of power) ; 



4. one self-recording navigation and oceanographic 

 sensor package 



5. one synchronous pinger; 



6. two 12 volt, wet cell battery packs. 



All but two of the instrument housings are constructed of 

 aluminum alloy for lightness. The sled's overall negative 

 buoyancy and its lateral trim are adjusted by small remov- 

 able lead weights. The fully equipped sled weighs approxi- 

 mately 250 kg out of water. 



For the BLM field study the logic package was timed to 

 trigger the camera and strobe at an exact 15 second repeti- 

 tion interval using crystal-controlled digital circuitry. 

 The time of day to the nearest second was optically regis- 

 tered in digital format adjacent to each film frame. 

 Pressure depth, magnetic heading, speed through water, temp- 

 erature, and conductivity were recorded on 1/4" magnetic 

 tape at 2 minute intervals. The pinger transmitted at 12 

 kHz at 1 second intervals with a mercury contact switch 

 set up to cause it to double ping if the sled tilted by 

 more than 30 . 



