of :aily inst partially ar _ + and armed coracles began on D-4 days. For Umbrella, placement of .cles began on D-5 days, with final arming being accomplished after the last test sig:.. ae afternoon of D-1 day. Although line-of-sight radio signals had been thought necessary, all stations received radio Signals with antennas placed 6 feet. above the ocean Surface. Installation and maintenance of the additional instrdments aboard the major target ShipS were accomplished by a Special crewusing available shuttle services. Thus, no special logistic support was required for this phase of the project. One FFP practice run, including the camera aircraft assigned responsibility for photomosaic coverage, was performed to gain operational experience in FFP placement, location, and recovery. Onthe basis of this experience, the operational procedure for Wahoo was planned. This plan was modified for Umbrella to include helicopter pickup of ali FFP’s, coupled with radar location of al! positions before and after the shot. 2.1.1 Shot Wahoo. The placement of deep moors for Shot Wahoo, beginning on 16 April, pro-~ceeded slowly because of unavoidable delays caused by high winds and difficulties Task Group 7.3 was having with the mooring of the major target ships. By 29 April, 5 moors had been placed; by 8 May, 12 moors; and by 14 May, all moors except D 4.8 and D 8.0, which had to be withheld until DD-592 was placed in the target array. Final arming of coracles could not commence until 11 May (D—5) because Edgerton, Germeshausen and Grier (EG&G) was having difficulties with radio-signal transmission. the following schedule: Final arming of coracles therefore was accomplished according to 11 May DL 12.0, DL 18.3, D 23.1, DR 24.0, CR 6.4; 12 May CL 3.9, CL 4.6, DL 7.1, DRR 6.8, CR 4.1; 13 May U 4.5, D 14.4, DR 4.5 (operationa: difficulties precluded further arming); 14 May U 3.2, DR 9.0, DR 14.4, DRR 12.8, CR 5.2; . 15 May U 4.0, D 4.8, D 8.0 (last two positions required both placement of moors. and arming). Shortly after 1600 on 15 May (D—1), an accidental radio signal triggered all coracles, thus canceling participation in the shot unless re-arming could be effected. The project therefore attempted an emergency re-arming operation the night of D-1. A priority list for the re-armtng of coracles was established, and the USS Munsee, which was working the array at the time of the accidental signal, was instructed to pull and re-arm coracles without interruption. All available project personnel, plus volunteers from Project 2.1, SIO, andthe USS Hooper Island (ARG-17) were ferried from Parry Island to the USS Munsee, where they formed three re-arming crews, which operated continuously until the ship was ordered to leave the array at H-2 hours. During this period of approximately 18 hours, 14 coracles were re-armed; however, the unavoidable fatigue and confusion that attended this work, combined with the necessity for rapidity, greatly increased the probability of instrument failure due to arming errors. The coracles finaly re-armed were U 4.5, CL 3.9, CL 4.6, DL 7.1, D8.0, DR 4.5, DR 9.0, DR 14.4, DR 24.0, DRR 6.8, DRR 12.8, CR 4.1, CR 5.2, and CR 6.4. At H-5 hours, a crew of five men returned to Parry Island to carry out previously planned shot day activities. Forty-eight FFP’s were dropped into the target array from two helicopters between H-2 and H-1 hours. No operational difficulties were experienced and all FFP drops were executed as planned (Section A.5). The first photomosaic was flown between H—1 hour and H~15 minutes at an altitude of 1,500 feet, a large number of FFP’s being visible from the aircraft. The FFP’s drifted 30 minutes longer than anticipated due to a delay in the shot and were moved an unexpected distance radially by water waves resulting from the detonation. At H+1 hour, a second drop of 17 FFP’s was made from an SA-16 aircraft concurrently with the postshot photomesaic. Also at H+1 hour an FS was recovered from the YC-2 barge by helicopter and returned to Parry island for Cl™ analysis and beta-gamma decay measurements. This helicopter and a second then returned to the target area to spot FFP’s for the Gy 52