armor wires are pre-formed and twisted around the center 

 electrical cable. They provide the necessary tensile strength 

 (15, 000 lbs. ultimate) and protection against abrasion and fish 

 bite. The inner layer is made up of thirty-two . 035" galvanized 

 high strength steel wires in right lay. The outer layer has thirty- 

 two . 042" galvanized high strength steel wires in left lay. This con- 

 struction has much less torque than single lay construction. For 

 additional corrosion protection the armor is imbedded in an outer poly- 

 ethylene jacket of .050" wall thickness. Total cable diameter is .615". 

 Weight in air is 440 lbs /1 000 ft. Weight in water is 310 lbs /1 000 ft. 

 Cable stretch was measured to be 0.64 ft. per 1000 ft. length per 

 1000 lbs. tension. 



3.1.5 Signal Cable Terminations (Vector Cable Co. Dwg. 13030) 



The electromechanical cable termination is designed to hold the 

 armor wires and make a pressure-tight electrical connection to 

 the instrument housing. These functions are accomplished by en- 

 capsulating the armor wires in an epoxy plug while connecting the 

 electrical cable to a pressure-tight electrical feed-through. An 

 assembly drawing is given in Figure 3-10. The conductors are 

 sealed even if the space inside the DAT (Double-Armored Termin- 

 ation) shell is flooded due to a break in the outer cable jacket or a 

 leak past the neoprene boot. Tests ha^^e proven that this termination 

 will develop nearly the full strength of the armor (failure of armor 

 strands will occur just outside the DAT shell). Tensile failures below 

 15, 000 lbs. that have occurred at this termination were due to im- 

 proper epoxy encapsulation. The armor wires were not adequately 

 hooked or sand-blasted to remove the zinc plating, or the epoxy was 

 not properly filled or formulated. It is believed that such failures 

 can readily be avoided by careful manufacture. We have found that 

 X-ray photographs are a useful final inspection tool. Proof testing 

 to 50-60% of ultimate strength is also recommended. 



3.1.6 Instrument Housings 



The instrument housings provide a one-atmosphere air environment 

 for the back side of the sensors and for the electrical wiring. This 

 technique was used for convenience in assembly, economy, and to 

 evaluate such housings for use on a future telescope which might re- 

 quire the use of electronic decoding and switching circuits at the sen- 

 sor stations. The housings are bolted to the DAT shells using flange 

 joints with double O-ring seals. If a housing should flood due to seal 



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