investigating deep underwater effects by detonating a weapon at sufficient depth to contain all the initial energy of the nuclear explosion in the water (16: 1-3). The Navy needed to know how a deep underwater shot would affect naval forces and, specifically, the answers to two leading questions: (1) What are the characteristics and lethal ranges of the resulting underwater shock wave? and (2) What are the effects of the radioactivity, following the explosion, on naval tactical operations? For example, could a surface vessel use a nuclear depth charge to destroy submerged enemy submarines without endangering itself? Specific answers to these questions were required to plan possible naval use of these weapons (16: 1-3,1-5). 4.12.2 WIGWAM Test Operations. Approximately 6,800 personnel and 30 ships participated in Operation WIGWAM. They conducted or supported the three scientific programs designed to collect the desired data (16: 9,1-3). A 6-mile towline connected the fleet tug, USS Tawasa, and the barge from which the nuclear device was suspended. Located at varying distances along this towline were a variety of pressure-measuring instruments, unmanned and specially prepared submerged submarine-like hulls (called squaws), as well as instrumented and also unmanned surface boats (16: 9). The ships and personnel conducting the test were positioned 5 miles upwind from the barge that suspended the nuclear device. The only exceptions were for USS George Eastman (YAG-39) and USS Granville S. Hall (YAG-40). These two extensively reconfigured ships, equipped with special shielding to prevent radiological exposure, were stationed 5 miles downwind from the barge. Recovery parties later reentered the test area with radiological safety monitors, and after aerial surveys showed the general location and size of the contaminated water area and the radiation levels (16: 9). 111