During World War II, the U.S. Navy performed some radical conversions of pre-war ships for them to be useful in the new era of three-dimensional warfare. Although numbered as destroyers, the eight ships of the 1,850-ton, 381- foot Porter class (DD-356-363) were conceived of as squadron leaders and equipped on the scale of light cruisers in foreign fleets. Their four twin, enclosed Mk 22 5-inch gunmounts were not equipped for antiaircraft service but were served by two non-stabilized Mk 35 main battery directors. Torpedo armament consisted of quadruple 21- inch mountings before and abaft the after stack, with a complete set of reloads flanking the after deckhouse and after stack in exposed, maindeck lockers. This early view of Selfridge (DD-357) shows the tripod masts and two of the quadruple 1.1-inch antiaircraft gunmounts—a weapon more potent than the standard U.S. Navy destroyer outfit of four .30-caliber or .50-caliber machineguns.
Initial modifications to the Porter class included deletion of the after main battery director and tripod mast, plating up most of the hull portholes, providing a variety of 20-mm and 1.1-inch or 40-mm guns, and adding four depth- charge mortars. Atlantic Fleet units like the Moffett (DD-362), shown here in March 1944, were employed primarily in escorting convoys in areas not subjected to heavy air attacks. They retained their low-angle 127-mm guns throughout their careers, but by mid- 1944, the superfiring 127-mm mount aft had been replaced by a quadruple 40-mm antiaircraft mount.
The Selfridge, McDougal, Winslow, and Phelps (DD-357-360), were given major reconstructions in 1944- Twin Mk 38 high-angle 127-mm mounts replaced the fore and aft Mk 22 mountings, while a Mk 30 single mount was located in the after, superfiring position. A British- style open bridge, surmounted by the director for the Mk 37 dual-purpose 127-mm gun-fire control system, was substituted for the original structure. A quadruple 40-mm mount was placed in the forward superfiring position. The Phelps is shown here in October 1944. In 1945, all four ships were earmarked to lose their torpedo tubes to an expanded antiaircraft armament, including three radar-directed quad and two twin 40-mm mounts, but only DD-359 and DD-360 had the work completed, and neither made it to the Pacific before the close of the war. Post-war, DD-358 and DD-359 (inset here in July 1945) became gunnery training ships AG-126 and AG-127, with the latter remaining active until 1950.