Force's Destroyer Flotilla 2 from the western seaboard into the Caribbean. Only for one brief period, in the autumn of 1934, was Wasmuth not fully active, being then assigned to Rotating Reserve Squadron 10. With the construction of newer, more heavily armed and far-ranging destroyers, the need for the old "flush-deckers" in their designed destroyer role diminished. While, of course, a great many of those World War I-authorized ships lay in reserve on both coasts, the Navy was expanding as the 1930s had progressed and, in view of ominous developments in Europe and the Far East, was broadening its operational horizons. Aviation-oriented and mine-warfare types of ships - seaplane tenders and fast minesweepers and minelayers - were needed. Accordingly, some of the old "flush-deckers" were converted to other roles. Wasmuth, a unit of the fleet in Hawaiian waters since the permanent basing of the ships there in April 1940, was among the Clemson-class ships chosen for conversion to high-speed minesweepers of the Chandler class. Wasmuth, reclassified as DMS-15 on 19 November 1940, underwent the metamorphosis at the Pearl Harbor Navy Yard. Retaining her full four-gun main battery and an antiaircraft battery of .50-caliber machine guns, as well as depth charge tracks, the ship lost her torpedo capability when minesweeping gear replaced her dozen torpedo tubes. Upon completion of that conversion at the Pearl Harbor Navy Yard on 5 April 1941, Wasmuth sailed for Palmyra Island and operated there until 19 April, when she set course to return to Pearl Harbor. The high-speed minesweeper subsequently remained in Hawaiian waters until 10 June, when she sailed for the west coast of the United States. Returning to Hawaii in early July, Wasmuth operated out of Pearl Harbor through the autumn of 1941, as tensions increased in the Far East. She operated on local patrol and minesweeping exercises during that time, as the fleet maintained an intensive training schedule. World War II Shortly before 0800 on 7 December 1941, planes from six Japanese aircraft carriers swept down upon the fleet units present at Pearl Harbor, in a surprise attack. Wasmuth (among the ships in port that Sunday) lay at buoys D-7 and D-7S inboard in a nest with three sister ships of Mine Division (MineDiv) 4: , , and , at the mouth of Pearl Harbor's Middle Loch and just off Pearl City. Wasmuth went to general quarters at once and Lt. (jg.) J.