CABLE ASSEMBLY WITH INTEGRAL HYDROPHONES 

 AND INSTRUMENTATION 



P. R. ANDERSON 



Westinghouse Electric Corporation 



Baltimore, Maryland 



INTRODUCTION 



The cable assembly described in this paper 

 was developed as a result of the need for a long 

 mult i- element vertical acoustic array that could 

 be raised and lowered in and out of deep water 

 rapidly by remote control without human super- 

 vision. The location of the equipment limited 

 the space available and required that a minimum 

 of space and weight be added, that storage be 

 automatic and that the entire array length 

 change direction at least 90 ■ It wa s also 

 important that the attitude and shape of the 

 array be known at all times. 



Many sophisticated storage and handling 

 arrangements were examined including methods for 

 Flemishing, spinning reel type storage, linear 

 cable hauler, capstans, etc. All methods had 

 serious faults for this application--too large, 

 too expensive, too complex, too slow, etc. A 

 simple arrangement with a large power driven 

 storage drum and an overboarding sheave to accom- 

 plish the change of direction, appeared to be 

 desirable if an array could be designed that 

 could be stored under tension on the drum and 

 flexed sufficiently to pass over a reasonable 

 size sheave. A requirement that operation be 

 remotely controlled eliminated the possibility 

 of storing array sections in short lengths and 

 assembling them as they passed over the side 

 even if a system could be developed that per- 

 mitted the rapid assembly necessary to meet the 

 raising and lowering speeds specified. 



DESIGN CRITERIA 



The final approach decided upon required the 

 development of an array in which the hydrophone 

 elements, preamplifiers if required and atti- 

 tude sensing elements although larger than the 

 cable in diameter, became an integral part of 

 the cable, without restricting the flexibility 

 required for changing direction and storage on 

 a drum. This approach itself immediately 

 initiated many problem areas. The strain member 

 and electrical conductors of the cable would 

 have to be concentric with the instrument pack- 

 ages . The packages themselves must maintain as 

 small a diameter and length as possible. An 

 array of this length would be difficult to manu- 

 facture in one continuous operation. The break- 

 out of individual leads to each array element 



must not weaken or disturb the continuity of the 

 strain member but the leads themselves must sus- 

 tain frequent f lexings without failure . Cable 

 diameter, even with 96 leads, must be kept to a 

 minimum but the strain member must provide a 

 satisfactory safety factor for reliability. 



The above problems required various solutions. 

 To maintain the cable leads and armour concentric 

 with the instrument packages, all units were 

 designed with a hole around their center axis 

 through which the cable could pass . A cylinder 

 with a hole through its center does not present 

 the most desirable volume in which to package a 

 hydrophone, preamplifier, tilt sensor or magnetic 

 bearing detector. The necessary components were 

 fitted into packages with an external diameter 

 of 2.5 inches and a maximum length of 3-5 inches 

 with a hole 0.8 inch in diameter for the cable. 

 An array of this type necessitated a hydrophone 

 with a high degree of insensitivity to accelera- 

 tion effects and the ability to operate at high 

 pressures in addition to the necessary acoustic 

 sensitivity and impedance. 



A stabilized transistorized preamplifier with 

 kO db gain was fitted into the desired package 

 configuration. Linear accelerometers, used in 

 pairs to measure cable deviation from the verti- 

 cal, were available that would fit the package 

 configuration. Magnetometer probes measuring 

 field strength by the even harmonic method were 

 found small enough to be packaged as an integral 

 part of the cable. 



A system was conceived by which the array 

 could be manufactured in short sections although 

 the final assembly would have the appearance of 

 one integral section. Although construction of 

 the array was facilitated in many respects by 

 assembling the entire length from short sections, 

 the multitude of connections necessary to pro- 

 vide continuity of the leads from section to 

 section presented a problem. A quick disconnect 

 type connector was considered but none was avail- 

 able with the necessary small size, sufficient 

 electrical connections and suitable strain member 

 connection. The lack of a quick disconnect con- 

 nector plus the other considerations resulted in 

 the method described here. 



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