was v damaged due to shock or base surge action, an estimated 90 percent of the maxi- ove. -uracles are considered valid, Since the most important phase of base surge transit mu - data was recovered from the target ships. Most of the records obtained from was often completed prior to overturn and since an apparently accurate although attenuated rec- ord of airborne radiation fields was obtained after overturn. There was, unfortunately, a high percentage of instrument failure during Umbrella due to a combination of cable failure and ex- hausted batteries. Both these difficulties can be partially attributed to the accidental firing during Wahoo, since the project supply of batteries was depleted and instrument cables neces- sarily received rough handling under the leSs~than-ideal re-arming conditions extant on the fantail of the USS Munsee. Because of these failures, little data exists on the downwind leg in the neighborhood of the DD-594; however, the highly successful FFP operation permits the constriction of isodese contours in this area. With the help of photographic data, these contours can be used to interpret the DD-593 records. In Summary, the data obtained by the project comprises: 1. Records of the total gamma dose rate as a function of time from unshielded detectors installed aboard 14 coracies and 2 target ships for Wahoo, and aboard 17 coracles and 4 target ships for Umbrella. These were recorded on magnetic tape for a period of 12 hours or longer after detonation and have an estimated accuracy of +30 percent after correction for detector response. 2. A Series of incremental collections of deposited activity taken at uniform time intervals after zero time at 11 coracle locations for Wahoo and at 13 coracle locations and 1 ship for Umbrella. These collections were counted for gamma activity after recovery of the coracles; hawever, since the degree of fractionation is largely unknown, the estimated activity at the time of deposition could be in error by an order of magnitude. 3. Records of the early gamma dose rate as a function of time with high time resolution from coracles at 2 locations for Wahoo and at 10 locations for Umbrella. These were recorded with a time resolution of 0.1 msec on magnetic tape for a period of approximately 80 seconds after detonation and are probably accurate to within +30 percent when corrected for detector response. 4. ° Records of the underwater gamma dose rate as a function of time from detectors placed below the ocean surface at 7 locations for Wahoo and at 4 locations for Umbrella. These were recorded on magnetic tape for a period of 12 hours after detonation with an estimated accuracy of +30 percent after correction for detector response. 5. Total gamma dose accumulated during the radiological event measured by film packs at all coracle locations and at approximately 20 locations aboard each target ship for both shots. Film pack data was also obtained at 10 additional locations within the Wahoo array and at 62 additional locations within the Umbrella array. The accuracy of the film dose is at least +20 percent. Additional samples collected primarily for other projects included total and time-based fallout collections and exposed test panels aboard the DD-592 for Umbrella only. Gross col- lections of fallout deposited on a 2'4-ft? area were obtained from time of fallout arrival to 1 hour after detonation by OCC collectors, and from time of arrival to time of cessation by AOC collectors. Standard test panels were exposed over the same time period specified for OCC collections. A series of fallout collections made at a constant sampling rate of 10 ft? min were obtained for a sequence of 10- and 2-minute Sampling intervais. Aboard the DD-593, additional OCC collections and exposed standard test panels were obtained for Wahoo and Umbrella. For greater convenience, information on shot yields and positions, together with meteorological conditions prevailing at the time of detonation have been obtained from the best available sources (References 75 through 81) and are summarized in Table 3.1. Similar data for Shots Baker and Wigwam and a summary of attendant radiation phenomena are presented in Appendix E. Page 78 was deleted ) O 17