and two water shots in the megaton yield range. A smaller array extend- ing to 15 miles was planned for the lower yield Echo shot.* 2.2 LAND AND LAGOON PHASE The land and lagoon phase of operations took plece at Bikini Atoll for Shots 1, 2, 3, and 4 and at Eniwetok for Shot 6. In addition exten- sive preparations for Echo were made at Enivetok. The instrumentation of the islend and the lagoon raft stations is discussed in Chapter 3. The preshot preparations at Bikini involved readying the e,uipment, . calibrating the instruments, and emplacing them at the island ond lagoon raft stations, This was completed a week prior to Shot 1. final checks were made on the equipment at all the existing stctions 1 to 2 days before shot time to assure complete readiness and operational efficiency. Freparations were also made for the r-covery operations and for the re-instrumentation of the stations. Participation in all detonations except Shot 5 was achieved 6lthough not to the extent originally planned. The lesser participation was due to the destruction of equipment by the fire:in the compound at Tare fcilowing Shot 1, Tables G.1 through G.20, Appendix G, show the degree of instrumentation and recovery for each shot. 2.3 SEA PHASE Free-floating buoys were selected for sampling fallout in the open ocean on the basis of their evalustion at IVY¥.U/ Each buoy station was so located that it was expected to drift to the desired positicn by shot time. Records were kept of the locations and times of placement and recovery of each buoy. From these data, positions at shot time were estimated by assuming that each buoy drifted in a straight line at a constant speed, It was essential that the time the buoys were at sea be held to a minimum so that their locetion at shot time could be estimted as accurately as possible. For this resson the array for each test was laid out within 36 hr of the proposed shot time and recovered as soon as possible afterwards. _ Sea phase operaticns were mounted from Eniwetok Atoll for all shots. Detailed direction, once Naval wmits were committed, was accomplished from ships based at Bikini Atoll or from vessels actively participating in Project 2.5a operations. 2.3.1 Pretest Preparetions The buoys and associated equipment were assembled and tested at Parry Island. Liaison was estublished with the Navel Task Group and plans for conducting the sea phase were made. These plans consisted of loading two sea-going tugs with s,uipment at Eniwetok Atoll, after which the vessels proceeded to sea to lay the buoys. After compietion of the buoy leying operctions, the tugs retired to a safe area to await the shot. Upon receipt of clearance from the Naval Task Group Commander following the shot, the tugs proceeded to recover buoys after which they returned to inivetok to off-load, * Not fired, Detailed plans for laying the buoys, 28 qe