assumed to be hazardous. Twenty-four hours travel of a CaSTLE cloud wes : assuned to be approximately 500 nautical miles, (b) CINCPACFLT was requested to make advance diversions of shipping outaide a sector area from southwest clockwise through north to east, to 500 nautical miles from ground sero from d to H plus 24 hours. This was accorplished on all shots; however, since the control involved primarily only U. S. shipping, arrangements were mace subsequent to GR.VO to effect maximuin coordination with other nationalities, «also, tbe excluded ares was changed to an officially designated Danger area subsequent to ER.VO and re-defined as the sector area centered on 12° N, 164° E, from 240° clockwise to 95°, radial distance 450 nautical miles, Within this sector an additional area designated areca CREEN was defined as the region bounded by 10° 15' N, 16° 4O' N, 160° 10" E, and 170° 20' EB. (The significance of area GHREN is discussed in 4.4(3)(c) below.) 4 further modification subsequent to BRAVO provided for all U. S. shipping passing within 600 nautical milos of BIKINI to come under the operational control of CTG 7.3 (for racsafe diversion if necessary) while within this linit, (e) P2V airereft were planned to sweep the significant forecast sector of fall-out, using visual and search radar methods of sightings out to 800 nautical miles on D mimes 2 days, cut to 600 miles on D minus 1 day and, if necessary, in front of the cloud on D Day, Since the reliable range of the P2V search redar was taken as thirty to fifty NM, the effective width of the sweep of a single P2V was (roung trip) 120 to 200 NM. ‘The P2v airereft crews were instructed to report the presence of any shipping sighted on D minus 2 day sweeps and to attempt to effect the diversion of 211 ships Signted on D minus 1 dey and D Day. .lthough this plan was used on Operetion 33