-16- RESULTS Initial radiation survey The Wahoo device was detonated at 1330 on May 16, 1407 hours, 1958, and at the radiation survey to determine the 10 mr/hr limits of the radioactive water mass was started. A summaryof the ship's track and the radiation readings in mr/hr recorded during the survey are presented in Figure 4. Immediately before the Wahoo test while the ship was 7, 000 yards south of target zero, the background radiation aboard ship was 2.0 mr/hr. The average background radi- ation in the target area was 1.5 mr/hr. In the following discussion the average background value has been subtracted from the values presented. Following the detonation, as the ship proceeded in a northeasterly direction, it entered a 3 mr/hr field, at which time (1435) it was turned to the west, During the turn, the radiation level increased rapidly to 500 mr/hr (1451) and then dropped rapidly to 5mr/hr as the ship's was changed sharply southward and away from target zero. course This point, approximately one mile southeast from target zero, probably represents the limit of the main body of radioactive water at this time (1455). survey was continued in a southwesterly direction and at 1510, readings of 10 to 30 mr/hr were obtained, a northwesterly one. the course was The when changed to At 1530, readings of 2 to 8 mr/hr were obtained - weco D ov 24, wb