patrol plans provided “that positive offensive action with all means at my disposal will be taken to prevent unauthorized entry within (the) closed area.” In the case of intruder submarines, both when submerged and on the surface, this action will be taken without identification, General Hull stated. In the case of surface vessels or aircraft, the plan provided that positive identification would be made to determine the character of intruders prior to taking offensive action. Outside the closed area, but within the danger area, General Hull stated in the radio, instructions provide for reconnaissance, tracking and warning to craft to leave the danger area. The radio message continued: “Experience to date indicates that these measures will not be effective in the case of foreign submarines which remain submerged; and may also create embarrassing delays in the case of unauthorized surface vessels. I know of no way to warn such a submerged submarine except by the dropping of depth charges in the vicinity but not aimed to hit.” General Hull, in his message, then asked that authority be granted him to take such action if necessity to do so should arise. On 11 March the Joint Chiefs of Staff approved General Hull’s plan, including authority to warn submerged submarines within the danger area by use of depth charges not aimed to hit, but accepting the risk of doing so. Additional authority was given that, as test days neared and if a submerged submarine failed to respond, warning could be intensified by aiming closer aboard. This action was concurred in by the State Department.2~ Although it is certain that submarines did corpe into the danger area, no occasion arose in which the warning action was taken. The closed area was never entered. Perfection of the evacuation plan was one of the goals of the Task Force at this time. This plan demanded the coordination of all Commanders and individuals as well. Two musters were to be taken on test minus one days, to account for all personnel. Results of these musters were channeled into the Task Force Headquarters immediately. A “Red Alert” for emergency search and a “White Alert” for search for unauthorized persons was devised. For personnel whose duties required them to remain ashore during tests, water and air emergency evacuation was provided. Initially, it was planned that all surface craft would move out of the lagoon into the open sea in an up-wind position during tests. This plan was modified prior to Peter Xray Day to provide that the four major ships of the Task Force, plus necessary small craft, would remain in the lagoon. All other surface craft were evacuated to the open sea. The Peter-Xray test began on 4 April 1948 (PX4) with the dispatch of a message announcing the weather briefing conference to be held on PX-3 day at 1500. The purpose of this conference was to provide the Commander, Joint Task Force Seven, with the necessary information upon which to base his decision whether or not to proceed with the evacuation plan, the first step to be undertaken in setting the test machinery in motion. (The decision for PX Day was to be affirmative regardless of conditions). The state of readiness of Task Groups proved to be the determining factor in this decision since the 72-hour weather outlook provided no firm basis. Weather predictions became a major factor on test day minus one. 1’ JCS series 1795. 123 .,.,.. ,.