(ilibiitishhieeee,: 10 March 1954 . MEMORANDUM FOR RECORD SUBJECT: Frotection of Transient Shipping During Operation CASTILE 1. In order to provide protection for transient shipping in the region immediately outside the Eniwetok/Bikini Danger Area during Operation CASTIE factors were established end a plan of action placed in effect as follows: ae Planning factors: (1) CASTLE clouds more than 24 bours old should not be hasardous (2) 24 hour travel of a CASTLE cloud should be approrimately 500 nautical miles. de Plan: ~ (2) NG (2) The Comsander in Chief, Pacifie Fleet was requested to wake advance diversions of shipping outside a sector area from southwest clockwise through north to east to 500 nantical miles from ground sero fros H to H plus 24 hours. P2V aircraft were planned to sweep the significant forecast sector of cloud travel, using visual and search radar methods of sightings coat to 800 nan- tical miles on D-2 days, cat to 600 nautical alles on Del day and, if necessary, in front of the cload on D day. P2V aircraft crews were directed to ef- fect diversion on all ships sighted in the sector area on Del ami D day. (3) W-2 aircraft on reutine weather reconnaissance missions were directed to report all sightings of surface shipping encountered. Ald sightings were to be relayed to the Radar center (CIC USS BAT=0zD) in the TG 7.3 fleet. (4) P2V aircraft and destroyer security sweeps were di- rected for the Eniwetek/Bikini Danger Area. Inform mation fron these sweeps was channeled to the Radar center (CIC USS BAIROKD). mma