COMPONENT SELECTION AND DESIGN 



Selection of Cable Type 



Several types of towing member have been used in comparable 

 applications. One such type is a segmented chain of rigid 

 links with provision for one or more separate electrical con- 

 ductors. Typical of such designs is the "thermistor chain," 

 developed by the Commercial Engineering Company in conjunction 

 with Woods Hole Oceanographic Institution (2), and successfully 

 used in obtaining continuous measurements of the temperature 

 profile. The largest such unit, in use by the Department of 

 Oceanography and Meteorology at the Agricultural and Mechanical 

 College of Texas, has a length of 900 feet. The significant 

 disadvantage of this towed system lies in its size and weight. 

 Since even the 900-foot unit is extremely bulky, this type 

 of equipment would hardly be practicable for use to a depth 

 of 5000 feet. 



Another type of towing member is a stranded steel cable 

 combined with one or more electrical conductors. In one de- 

 sign , a conventional wire rope center is employed as a strain 

 member; the insulated electrical leads are wrapped around 

 this core, and the whole is enclosed in insulation. An alterna- 

 tive design, known as armored cable, has the electrical mem- 

 ber, either multi-^conductor or co-axial, as the core with the 

 steel wires wrapped around the outside in one or two layers. 



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