2000 pounds in water. Steel was used in lieu of concrete to minimize the 

 physical size of the weight and to ease shipboard storage and handling. A 

 110 pound "Bruce" anchor was attached to the depressor weight. This 

 provided the necessary horizontal holding force to fix the end of the array 

 on the sea floor. An EG&G Model 322 acoustic release, installed in-line 

 between the "Bruce" anchor and depressor weight, provided a means to release 

 the sweepline from the bottom, figure 5. 



The upper sweepline weight was designated the sentinel weight. This 

 4500 pound (in water) steel cylinder was attached to the array 600 meters 

 above the depressor weight. Its purpose was to create the horizontal attitude 

 of the sweepline. Attachment of the sentinel weight to the array, where the 

 cable would make a transition from a horizontal to a vertical orientation, 

 was made in such a way that a sharp bend in the cable was precluded, figure 6. 

 A pinger and an acoustic release were attached above the sentinel weight to 

 provide vertical and horizontal positioning information, figure 7. 



Seven grapnels, designed and fabricated at NAVOCEANO, were distributed 

 along the center portion of the sweepline. These were designed to hook the 

 %-inch wire rope mooring line and wedge it into a sharp-edged V-notch, 

 figure 8. It was intended that this cutting action would damage the cable 

 enough to cause it to fail in tension. 



V. Determining Array Geometry - Catenary Analysis 



As previously noted, the recovery operation was carried out at very 

 low speed. This condition was imposed to permit a static analysis of the 

 cable geometry to be made thus providing the required information concerning 

 the vertical configuration of the cable during the sweeping operation. Given 

 the positions of the ship and sentinel as determined from acoustic ranging to 

 the transponder net and the altitude of the sentinel using a pinger, the exact 

 altitude of the sweepline at any point along its length was determined. Thus 

 it was possible to control the sweepline altitude by either varying the ship's 

 position or by varying the amount of cable payed out. 



The geometry assumed by the sweepline and cable with fixed anchor and 

 sentinel weight formed two distinct catenaries joined at the sentinel. This 

 geometry is illustrated in figure 9. The anchor and depressor weight are at 



point A with the sentinel weight at point B. The arclength AB is the 



sweepline which forms one catenary while the rest of the cable, arclength BC, 

 forms the other. 



In order to set up the catenary analysis, it was necessary to decide 

 what parameters were known or could be determined by direct measurements, and 

 what variables would have to be calculated from the analysis. Tables of fixed 

 constants, measured parameters and calculated variables were set up. The 

 nomenclature for these values are given in tables 1, 2, and 3 on page 10. 



Table 1 cites the "Fixed Parameters." These values would not change 

 during the retrieval operation, but were input values that could be changed 

 at any time up until the actual operation commenced. The linear density of 



