- 32 - 



5. The Water-Tight Instrumentation Cylinder 



The water-tight cylinder, located underneath the spider, is 

 an anodized aluminum pressure-tested housing developed by Sea-Data 

 Corporation. Four sacrificial zinc anodes are positioned about the 

 top of the cylinder. All of the pressure tubing penetrates the top 

 (removable) section of the cylinder, while the power and data cable 

 connects to the bottom via Brantner underwater XSL-20 connectors, 

 (Figure III-6) . The cylinder is held in place within the fuselage by 

 PVC blocks bolted to the fuselage walls with Monel fasteners. 



The transducers are held inside the cylinder by a series of 

 five wafers separated by acrylic rods. The bottom two wafers support 

 two of the differential transducers, the middle two support the 

 remaining two differential and one absolute transducer, and the upper 

 attaches to the underside of the cylinder top and suspends the wafer 

 assembly. The wafer and transducer stack is shown in Figure III-?. 



6. The Cable and Service Box 



The instrument is cabled to shore for power requirements and 

 data delivery. Eleven hundred feet of Blake BC 4960-1 double armored 

 cable is laid between the instrument and the land-based recording 

 facility. The cable is an eighteen conductor (18 gage - tin/copper) 

 strand wrapped around a polypropylene filler. Th^ conductors are 

 water-blocked, wrapped in mylar tape, and sheathed under a 



