The Inner Mooring was lowered from the Pontoon Barge, an 80 ft. 

 assemblage of 6 bridge pontoons upon which we installed a mammoth 

 braked drum which had been laying idle at Navy Operating Base (NOB). 

 This drum is capable of paying out a tremendous weight (never measured) 

 when braked, but can winch in only a 1000 lb load; hence the Inner 

 Mooring could not be hauled up except by the YC-1378. Signal cable 

 and wire rope were loaded on the YC-1378 under tension at NOB 

 (approximately 1/3 pay-out tension). The barges and loading rig 

 are illustrated in Fig. 5-3. The YC-1378 drum winched the cable 

 in at the desired tension against the drag provided by the braked drum 

 on the Pontoon Barge. The cable or wire rope was fed naanually onto 

 the braked drum, passed four turns around the drum, then around a 

 36-inch block (tied down to the deck of a YD crane 200 ft. away), 

 and run back to the cable drum on the YC-1378 which was tied up 

 out board of the Pontoon Barge. Tension was measured by a Dillon 

 Gauge in series with the 36 inch block tie-down line. (This tie-down 

 line was sized to be the weak link in the system. ) 



5. 4 Outer Mooring Implantment 



The Outer Moorings were lowered in place anchor first from the 

 YC-1378 barge under tow from the tug boat, T-426 (see Fig. 5-4). 

 The taut configuration of these moorings after initial implantment 

 is illustrated in Fig. 5-6. After the Coral Hook and Chain were 

 slipped off, the full weight of the system was taken on the wire rope 

 mooring line. Tension reached a maximum of about 3500 lbs. just 

 before the floats were submerged. In order to minimize the danger 

 of slackening or overstressing the cable due to wave-induced dynamic 

 motions, we calculated a GO-NO-GO limit for acceleration of the 

 barge stern. Because we stayed in port during rough weather, this 

 limit, 0. 50 "g", was never reached at sea. If it had been reached, 

 we would have returned to port before slipping off an anchor. 



Because of the aforementioned unsuitability of the vertical axis 

 drums, we experienced much difficulty with dropped turns of the 

 Western Outer Mooring line wound last on the drum Several times 

 this necessitated stopping the wire rope with Cline grips, re- 

 winding many turns, and the repairing of the polyethylene wire rope 

 jacket where the grip had been applied. Fig. 5-5 illustrates the 

 dropped turns encountered when the signal cable was loaded on the 

 drum. When the top of the 101 ft. shot reached the stern roller, 

 the port drum was braked and the load taken up on a synthetic line 

 which had been wound on the starboard drum. This synthetic line 

 was 8-strand, plaited, l-Lnch diameter POLY PLUS (Wall Rope Works), 

 nearly torque-balanced to minimize the danger of putting turns into 

 the mooring line. 



228 



