environments, as dependent on the movements and operations of each ship, and determines the daily exposure potential. Shipboard radiation surveys indicated a considerable variation in topside intensities because of ship geometry, redistribution of fallout during washdown and decontamination, and non-uniform adherence of fallout particles to ship materials. If only an average survey reading was reported, this value is used. In those cases where readings were taken at many predetermined positions on the ship's exposed surfaces, they represent the topside radiation field. The ship's crew is presumed to have been located at random positions when on deck; thus, mean survey readings, appropriately decayed, are used to determine the mean intensities encountered by the crew whentopside. Average topside intensities are also used where water shine or ship shineis involved. The limited data from Operation CASTLEthatrelate shine levels to radiation source strength are supplemented by radiation transport calculations that accommodate specific ship geometries. The analysis of radiation exposure to the crew also requires estimation of radiation intensities below deck and the apportionmentin time of crew activities below and topside. In addition to ship contamination, the fallout on deck has been noted as a contributor to below-deck intensities. A ship-shielding factor is defined as the ratio of the intensity below to the mean intensity topside from fallout. This factor, previously determined for each type of ship of interest ‘in Reference 1, is roughly 0.1 and is nearly constant over the usual crew locations within a ship. Thus, the time spent topside usually dominates the fallout dose. In some cases, specific durations of topside exposure are given in ship logs for shot day (rarely thereafter) when the radiological situation altered the normal pattern of duties. Otherwise, the fraction of time spent topside is assumed to be 0.4. This follows from reasonable topside intervals such as 0800-1200, 13301700, and 1800-2000 hours. The calculated dose to the crew is obtained from time integration of intensity for all intervals below and on deck; a conversion factor is used to account for body shielding by the badge wearer (Reference 5). Day-by-day and cumulative film badge doses to the average crewman of each ship are calculated and presented in section 4. Calculations are continued to the endofthe operation and into the post-operational period until the dose accrual falls below 1 mrem per day. An uncertainty analysis of the dose calculations is provided in section 5. In section 6,the available dosimetry records are analyzed and compared with the calculated doses. Conclusions and a total dose summary are presentedin section 7.