Figure N-9. Film selection graph. 



300 meters, lock the shutter open. Set the aper- 

 ture according to lens setting guide (fig. N-9). 

 For shallow water operation, unlock shutter 

 and refer to instruction manual for external 

 wiring. 



Step 6. Replace cameras, light sources, bat- 

 teries, and timing devices in their housings. 



Step 7. Inspect "O" rings and sealing sur- 

 faces of liousing ends and rear end caps for free- 

 dom from cuts, scratches, dirt, etc. ; apply a light 

 coating of grease on the "O" rings and the seal- 

 ing surfaces. Install rear end caps and tighten 

 clown thumbscrews (thumb tight only). It is 

 important that good seals be maintained be- 

 cause an implosion in deep water will destroy 

 the instrument. See figure N-10. 



N-11 Positioning Underwater Camera Com- 

 ponents on Mounting Rack. — For stereo oper- 

 ation, the components usually are mounted as 

 sliown in figure N-11. The cameras are mounted, 

 using a straightedge to aline their end caps. 

 Clamps are placed around the main housing 

 cylinder of the components and not over the 

 end caps. Reflectors are placed as far back as 

 possible on the flashtube covers and secured witli 

 hose clamps and electrical tape. All components 

 are positioned to balance the i-ack. The pinger 

 transducer is mounted in the center of the rack, 

 and the driver and transformer are positioned 

 near the transducer. 



N-6 



Figure N-10. The unit at the top of the photograph 

 was imploded at depth because of a faulty seal. Note 

 the total destruction of internal components. 



C CAMERAS 



L LIGHT SOURCE 



B BATTERY PACK 



D PINGER DRIVER 



T PINGER TRANSDUCER 



X TRANSFORMER 



®1 



(S 



3 



Figure K-11. Relationship of components for a stand- 

 ard stereo mounting arrangement. 



N-12 Electrical Connections Between Com- 

 ponents. — After the components are positioned 

 on tlie mounting rack, the external electrical 

 connections are made as follows : 



Step 1. Using connector wires with female 

 fittings, construct two watertight splices, a five- 



