CHAPTER 7 



UNDERWATER PHOTOGRAPHY 



7-1 GENERAL REMARKS.— Recent years 

 have seen a marked increase in the development 

 and use of underwater photography. Location 

 and identification of sunken vessels and other 

 submerged objects, studies of shellfish beds, 

 studies of fish and other biological life, studies 

 of reefs and coral growth, and studies of the 

 ocean bottom in relation to its sediment struc- 

 tures are a few of the many uses of underwater 

 photography. 



The newest medium to be utilized in the field 

 of visual underwater observations is television. 

 Although at present limited to relatively shallow 

 water use, it has been successfully applied in 

 salvage operations. The potential uses for 

 such an instrument are great, and include 

 action studies of various types of equipment 

 either lowered into or towed through the water. 



7-2 Underwater Cameras. — Underwater 

 cameras may be classified under two general 

 categories; those operated by divers and swim- 

 mers, and those that are lowered with a winch 

 and remotely operated by bottom contact, 

 messenger, or mechanical means. The first 

 category includes both still- and motion-picture 

 cameras using either color or black and white 

 film. The second category usually includes 

 only still cameras. One type is the single shot, 

 taking only one picture on each lowering. 

 Another type is the multiple shot, taking a 

 series of pictures during the lowering operation. 



7-3 INSTRUCTIONS FOR OPERATING 

 THE SINGLE-SHOT BOTTOM CONTACT 

 CAMERA. — The single-shot, bottom-contact 

 camera is designed to obtain photographs of 

 the ocean bottom at great depths. It will take 

 one picture on each lowering, and the camera 

 shutter is tripped by contact with the bottom. 

 The tripping mechanism obtains a small 

 Phleger-type core at the time of tripping. 

 The camera is contained in a heavy pressure 

 case capable of withstanding water pressures 

 up to 12,000 pounds per square inch. It has 

 taken successful photographs at depths greater 

 than 3,000 fathoms. 



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7-4 The Camera Assembly. — The camera 

 assembly consists of a canvas vane, the camera 

 pressure case, camera, photoflash pressure case, 

 battery and firing mechanism pressure case, 

 trigger mechanism and coring tube, all of which 

 are mounted on a frame of aluminum tubing 

 14 feet long (fig. 7-1). 



The assembly is attached to the oceanographic 

 wire by a shackle at the top of the frame. A 

 small canvas vane is mounted near the top in 

 order to reduce spinning of the camera assembly 



CANVAS VANE 



CAMERA AND 



PRESSURE 



CASE 



BATTERY CASE 



MICRO-SWITCH AND 



BATTERIES 



CONNECTOR ARM 



SPRING 

 SLIDING SLEEVE 



Figure 7-1. Single-shot underwater camera assembly. 



H. O. 607 



