04/01 Thu. United States Naval Operating Facility, Grondal, Greenland, is established. Naval Air Station, Patuxent River, Md., is established. 04/03 Sat. Japanese naval vessel sunk: Submarine chaser No. 13, by submarine PICKEREL (SS-177), off Japan, 43 d. 03' N., 141 d. 58' E. 04/05 Mon. Japanese submarine sunk: RO-34, by destroyer O'BANNON (DD-450), Solomon Islands area, 08 d. 15' S., 158 d. 58' E. 04/07 Wed. Submarine TROUT (SS-202) lays mines near Sarawak, Borneo. Japanese aircraft make heavy strike against United States naval vessels near Tulagi, Solomon Islands. United States naval vessel sunk, Tulagi, Solomon Islands: Destroyer AARON WARD (DD-483) and oiler KANAWHA (AO-1), by horizontal bombers. United States naval vessel damaged, Tulagi, Solomon Islands: Cargo ship ADHARA (AK-71) and oiler TAPPAHANNOCK (AO-43), by dive bombers. 04/09 Fri. Rank of Commodore, United States Navy, is reestablished. Japanese naval vessel sunk: Destroyer ISONAMI, by submarine TAUTOG, (SS-199), off Celebes, 05 d. 26' S., 123 d. 04' E. 04/10 Sat. United States naval vessel sunk: Submarine TRITON (SS-201), Pacific Ocean area, reported as presumed lost. 04/15 Thu. Carrier YORKTOWN (CV-10) is commissioned at Newport News, Va.; this vessel is named fro carrier YORKTOWN (CV-5), sunk 7 June, 1942, after the Battle of Midway. Italian submarine sunk: Archimede, by naval land-based aircraft, (VP-83), off coast of Brazil, 03 d. 23' S., 30 d. 28' W. 04/17 Sat. German submarine sunk: U-175, by Coast Guard cutter SPENCER (PG-36), North Atlantic area, 48 d. 50' N., 21 d. 21' W. 04/18 Sun. Admiral Yamamoto, Commander in Chief Japanese Combined Fleet, is killed when his aircraft if shot down by Army aircraft. 04/19 Mon. Submarine SCORPION (SS-278) lays mines off Kashima Nada, Japan. 04/20 Tue. Submarine RUNNER (SS-275) lays mines near Hong Kong. 04/21 Wed. Submarine STINGRAY (SS-186) lays mines near Wenchow, China. 04/22 Thu. Japanese aircraft bomb airfield at Funafuti, Ellice Islands. United States naval vessel sunk: Submarine GRENADIER (SS-210), by enemy air attack and scuttling, Straits of Malacca. 04/23 Fri. Japanese naval vessel sunk: Patrol boat NO. 39, by submarine SEAWOLF (SS-197), off Formosa, 23 d. 45' N., 122 d. 45' E. 04/26 Mon. Task group of 3 cruiser and 6 destroyers (Rear Adm. C. H. McMorris) bombards Japanese installations at Attu, Aleutian Islands. United States Naval Station, Mers el Kebir, Morocco, is established. 04/27 Tue. German submarine sunk: U-174, by naval land-based aircraft (VB-125), North Atlantic area, 43 d. 35' N., 56 d. 18' W. 04/29 Thu. Submarine GATO (SS-212) lands coast watchers at Teop Island, Solomon Islands, and evacuates missionaries. 04/30 Fri. Submarine GUDGEON (SS-211) lands personnel and equipment on Panay, P. I. Submarine SNOOK (ss-279) lays mines off Saddle Island, China. United States Atlantic Fleet turns over responsibility for convoys between Halifax and United Kingdom to British and Canadian naval forces.