Step 5. Remove rear end cap from the Model 

 280 battery pack, and set the time delay switch 

 to allow enough time to lower the camera to the 

 ocean bottom. Camera system normally is low- 

 ered at approximately 60 meters per minute. 

 Replace end cap. Connect On-Off lead. 



Step 6. With the sliip lying to, hoist the cam- 

 era system over tlie side with a boom or crane, 

 and commence lowering (fig. N-16). 



N-15 Bottom Positioning Techniques. — 



When lowering the camera system, the descent 

 is controlled by monitoring the pinger-to-bot- 

 tom distance. During the cameras drift across 

 the area to be photographed, the distance above 

 bottom also is controlled by monitoring the 

 pinger-to-bottom distance. Chapter R, Sonar 

 Pinger, should be reviewed by the operator be- 

 fore attempting a camera lowering. It is most 

 important that the camera be kept within 20 

 feet of the ocean floor.throughout the operation, 

 yet care must be taken to avoid striking into the 

 bottom. 



Record the time the camera reaches the bot- 

 tom, and while the camera is photographing the 

 bottom (approximately 125 minutes), record 

 the ship's position at 15-minute intervals if pos- 

 sible. "\tnien the run is completed, bring the cam- 

 era system to the surface, and complete the 

 camera lowering log. 



N-16 Emersion of Camera and Removal of 

 Film. — "Wlien the camera is at the surface, hoist 

 the camera and place it on deck with a boom 

 or crane, insuring that it is well secured. First 

 the pinger should be unplugged, and then the 

 camera should be checked by listening to deter- 

 mine whether the film advance motor is still 

 running. If the motor is still numing, it is a 

 good indication that the lowering was success- 

 ful. Permit the unit to come to ambient tem- 

 perature or rinse the camera housing with hot 

 water before it is opened ; otherwise, the differ- 

 ence in temperature between the interior of the 

 mechanism and the surrounding air will cause 

 condensation on the camera chassis and the film. 

 Usually, the camera housing is not removed 

 from the mounting i-ack l^etween lowerings; 

 therefore, a changing bag sliould be used for 



removing the chassis from the housing. Exposed 

 film container and reel should be labeled with 

 the lowering number, camera serial number, 

 and time and date (GMT) . 



If the camera motor is not rvuining, check 

 the camera housing window to see if flooding 

 has occurred. If flooded, drain the water from 

 the camera by opening the lower end cap. Re- 

 move the chassis from the housing. Rinse with 

 fresh water and dry in an oven before attempt- 

 ing rejDairs. 



Figure N-IS. 



Hoisting underwater camera system 

 over the side. 



N-17 Processing of Film. — A few exposures 

 of each roll of film usually are processed aboard 

 ship to insure that the camera is functioning 

 properly (fig. N-17) ; however, better quality 

 pictures generally can be obtained by processing 

 film at a shore installation. 



N-18 Selection of Film. — The selection of 

 film to be used is dependent on several factors : 

 Quality of photograph desired, amount of light 

 available, the desired distance above bottom, 

 and the limits of the aperture settings. Black 

 and white or color film can be used. The graph 

 in figure N-9 is presented as a guide. 



N-9 



