Having lowered the array to 100 meters off the bottom, the run 

 toward the targeted drop point for the anchor began. As previously stated, 

 the run was made directly into the wind and seas at speeds below one knot. 

 Figure 17 illustrates the targeted drop points, one for passing MAVA 

 on the right, the other for passing MAVA on the left. 



Due to deep ocean currents, a deflection of MAVA from the vertical 

 was anticipated. Potentially this could cause premature interference between 

 MAVA and the recovery array if the horizontal sweepline were laid too close 

 to the MAVA anchor. To avoid this situation, the maximum deflection of MAVA 

 was calculated using a subsurface moored array design program. Figure 20 

 shows the results of this computer analysis. The curves represent the 

 deflected configuration of MAVA in unidirectional, constant velocity current 

 profiles. Ocean current data for the recovery area indicated a .2 knot current 

 at the buoy decaying to .1 knot on the bottom. Assuming a .3 knot worst case 

 situation, it was determined that the sweepline should be laid no closer than 

 215 meters from the MAVA anchor, figure 17. The shaded area of figure 17 

 was chosen as the acceptable area within which we could anchor considering 

 the length of the sweepline, placement of the grapnels and the desire to per- 

 form the sweeping operation while heading into the wind and seas. 



A plotting sheet was usdd which had a one inch grid divided into 



tenths of an inch. Positions were plotted at a scale of 1 inch = 400 meters. 



A plotting resolution of 10 meters was easily obtained. Figure 21 is a 

 reproduction of the plotting sheet. 



At 1600 hours on 12 December, the array was lowered to the bottom 

 and 100 meters of slack cable was payed out. The drop point choserl was the 

 one on the left in Figure 17 The positioning data indicated that the anchor 

 was dropped within 20 meters of this point. The ship was maneuvered to guide 

 the sentinel to the left of MAVA by at least 215 meters. Ship and sentinel 

 positions were plotted every three to five minutes. For many of the fixes, 

 the three position radii from the net transponders crossed at a single point 

 providing welcome reassurance during an anxious period. 



Maneuvering of the ship was accomplished by making appropriate changes 

 in engine RPM, rudder angle, bow thruster power and direction while observing 

 compass heading, wind speed and direction, and "course-made-good." The major 

 advantage of deploying and positioning the sv/eepline while heading directly 

 into the wind and seas was being able to precisely control the ship's posi- 

 tion and speed. The 20-25 knot winds were used to advantage in two ways. 

 First, movement of the ship from the anchor point was limited by throttling 

 back and using the wind and cable tension to slow or back the ship as 

 required. Secondly, during the sweeping maneuver, the wind was used to 

 "sail" the ship around MAVA by maintaining a heading slightly off the wind 

 thus causing the ship to crab in the desired lateral direction. 



As the ship progressed, cable was payed out at approximately 10-15 

 m/min. The pinger indicated that the sentinel was moving to its desired 

 altitude. At approximately 1700 hour, one hour after anchoring, the sweep- 

 line had been extended. The sentinel was 460 meters from the anchor point 



14 



