Table 1.1. Shot Name Operation CASTLE shot data. Local Date (time) Yield Location BRAVO i MarS4 (0645) 15 Mt Bikini (Sand pit off Nam Island) ROMEO 27 Mar 54 (0630) Ll Mt Bikini (Barge, BRAVOcrater) KOON 7 Apr 54 (0620) 110 Kt Bikini (EnemanIsland) UNION 26 Apr 54 (0605) 6.9 Mt Bikini (Barge off Iroij Island) YANKEE 5 May 54 (0610) 13.5 Mt Bikini (Barge, UNION crater) NECTAR 14 May 54 (0620) 1.69 Mt Enewetak (Barge, MIKE crater). 1.2 NAVAL PARTICIPATION. The nuclear tests were conducted by a joint military organization designated as Joint Task Force Seven (JTF-7). Although military in form, it was comprised of military, civil service, and contractor personnel. JTF-7 was organized into five main task groups, with Task Group 7.3 being the naval contingent. Most of the approximately 6,000 personnel assigned to TG 7.3 were aboard the various task group ships; however, approximately 650 were stationed on Enewetak and Kwajalein Atolls. Table 1.2 lists the TG 7.3 ships and the task units to which they were assigned, for which dose reconstructions are specifically addressed in this report. Also tabulated are the approximate number of personnel assigned to each ship. 1.3 METHODOLOGY. In Reference 1, procedures developed in previous dose reconstruction efforts were adapted to the shipboard radiological environments of Operation CASTLE. The basic procedures used in Reference 1 have been utilized in this companion report. Each step is pursued to a level of detail governed by the availability of data. Sufficient data were recorded at the time and enough have survived to understand the ship and land operations and to characterize the radiation environment. Individual ship deck logs (Reference 3) serve as an authoritative source of ship position and activity. Radiation intensity data and crew activity scenarios are applied to reconstruct the timedependent radiation environment for a typical crewman on each of the eight ships of interest.