The rafts consisted of alabs of styrofoam approximately 5' x 5' x 4" fitted with small radio homing transmitters and ballooneelovated transmitting antennas, The rafts were cropped from transport aircraft starring several hours before shot time, wero, The area covered was a 90° sector centered on ground The orientation of the sector was determinec om the basis of the latest forecast winds and forccast fallevat sone, Post-shot, two survey aircraft with large, highly sensitive scintillation-type counters were used ts locate the rafts and measure the intensities sf the ecntamination expected to be trapped in the porous styrcfoam. although Locetion of the rafts prcved to be the major operational problem (very few were found), the chief cause of failur of the project was due ts the fact that intensities on the rafts were act appreciably different from the intcnsitics read ower the water near the rafts, Sortunately, however, failure of the raft program for tha latter rezson point= ed the way toward a simpler and more practical methed of measuring the dcwnwind fall-out, namely, the use of lowelecwel aireraft flights to execute a grid-pattern survey cover the fall-out area taking readings of the intensity of the water itself. On the basis of the rclatively sketchy results from Y.NKEE, the KiSL group set up amd exccutod a reasonably succossful aerial water survey project for the last shot, NECTAR. (Note: CASTLE Project 2.58, having lost thebulk of their open sea dan buoy fall-out collectors duc to operational recovery problems and shot delays, also attacked the fall-out problem in a similar fashion. In general, the 2.5a plan on the last two CaSTLE shots consisted of gathering water samples from varicus depths to determine redistion intensities and the waricus parameters affecting the mixing properties of the ocean and the taking of vertical radiation profiles by means of trollin & submerged radiac instrument.) The results of the HiSL NYKOFO effort anc the 45