Anodized aluminum was used for the 

 housing to combine corrosion resistance, 

 minimum weight, and maximum strength. To 

 withstand the 455 pounds-per-square-inch 

 pressure at depth of 1,000 feet, the housing 

 wall was made 7/16 inch thick and the 6- 

 inch-dizuneter window at the front of the 

 camera was made of 1-inch-thick tempered 

 plate glass. For a detailed discussion of 

 camera-housing requirements for underwater 

 use, see Edgerton and Hoadley (1955). 



The window, the back plate, and the 

 cable connector were sealed with neoprene 

 0-rings to prevent lesikage. The connector 

 is of a special type designed for ease of 

 connection and removal of the cable (Appen- 

 dix figure A-1), a great operational advan- 

 tage in using underwater television. 



3. Ruggedness, reliability, simplicity , 

 and ease of access for maintentince . 



The design of the above-water equip- 

 ment (control unit and power supply) incor- 

 porated the normal precautions used with 

 cUiy marine electronic gear. All units were 

 properly mounted to prevent excessive vibra- 

 tion and shock. Becciuse space is normally 

 a problem aboard vessels, the above-water 

 equipment was designed for compactness; all 

 components were housed in two major units 

 (D and E shown in figure 1). 



The neoprene-coated cable connecting 

 the camera to the control unit was rein- 

 forced internally with a stainless-steel 

 core providing a tensile strength of appro- 

 ximately 5,000 pounds. During normal use 

 the c£ible is not subjected to more than 500 

 pounds' tension. Where severe strain is 

 not likely to be encountered, a cable with 

 a fiber core rated at 2,500 pounds can be 

 used. Fiber-core cables eire easier to han- 

 dle because they are more flexible and less 

 likely to kink. 



The electronic con^jonents were her- 

 metically sealed where possible, to provide 

 further protection against leakage, con- 

 densation within the housing, and the usual 

 extreme humidity at sea. In addition, all 

 components were spray-coated with a mois- 

 ture-resistant plastic. "Ruggedized" tubes 

 and special mountings were used for protec- 

 tion against shock. 



The camera, which generates consider- 

 able heat in operation, is cooled only by 



the surrounding water. Because overheating 

 of the camera pickup tube can create seri- 

 ous operational problems, a temperature- 

 sensitive element in the housing warns of 

 excessively high temperatures. 



A moisture indicator signals the pre- 

 sence of water in the housing to minimize 

 water deunage to the camera in the event of 

 a leak. The sensing element is shown on 

 the inside facing of the front ring of the 

 camera in Appendix figure A-3. 



The equipment was constructed in such 

 a way that the camera could be removed from 

 the housing simply by disconnecting the 

 back plate and sliding out the whole unit, 

 thus providing for ease of maintenance. 

 The slender camera unit was encased in a 

 perforated cylindrical sleeve to give it 

 added rigidity. The various components 

 were arranged to provide ready access for 

 servicing. 



4. Maximum versatility and adaptability . 



The camera unit was equipped with 

 three lenses of different focal lengths to 

 provide for versatility in operation. Any 

 of the three lenses may be brought into use 

 in about five seconds through a remotely 

 controlled, motor-operated lens turret. A 

 remotely operated iris diaphragm was pro- 

 vided. 



A very important feature was "gamma 

 adjustment" which improves definition of 

 underwater objects by providing control of 

 gray shade. This was provided because 

 underwater scenes generally lack contrast 

 and appear very "flat." 



An electronic process called blanking 

 (which means elimination of the bright 

 traces of the scanning beam from the end of 

 one linfe on the screen to the beginning of 

 the next) was provided for in the preampli- 

 fier. This is an important feature because 

 it allows for interchange of cables of 

 different lengths without the time-consuming 

 process of removing the camera from the 

 housing for adjustment. 



Lights and fins were attached with 

 brackets in such a way that they could be 

 easily mounted on or removed from the hous- 

 ing. All-aluminum attachments were used 

 whenever possible. When parts made of other 

 metals had to be attached to the aluminum 



