In addition to 403 173-foot PC-class patrol craft ordered for the U.S. Navy in 1941, 18 173-foot hulls were ordered for use as minesweepers, as the Adroit class. Built by five yards, all but three of the minecraft variant had been commissioned by the end of 1942, and the last entered service the following June. Unlike the PCs, AM 82-99 were given names: Adroit, Advent, Annoy, Conflict, Constant, Daring, Dash, Despite, Direct, Dynamic, Effective, Engage, Excel, Exploit, Fidelity, Fierce, Firm, and Force, respectively. As completed, they differed from the PCs in having a large sweep-cable reel mounted on the first platform deck and protruding through the main deck at the stern, in place of the after 3-inch or 40-mm gun mount; a slightly longer superstructure, surrounding the squat dummy funnel at its after end; a kingpost and boom fitted to handle minesweeping gear and the 16-foot wherry; and two davits at the stern to handle sweep gear and reload depth charges.
AM 82 through 88, built at Portland, Oregon, saw service throughout World War II in the Pacific. Only the Annoy (AM-84) is recorded as having been used to sweep for mines, in Aleutian waters; the others principally were employed as convoy escorts in the dangerous waters of the southwest Pacific. The other 11 operated initially either from Bermuda (AM-89-93) or from mainland U.S. bases, again as convoy escorts. That they were far more useful in an antisubmarine role than as minecraft was realized quickly, and the 11 Atlantic units were cycled through the Norfolk Navy Yard during May and June 1944 to have their mine countermeasures gear removed and additional antisubmarine and antiaircraft ordnance added. The Pacific units were modified at Pearl Harbor. On 1 June 1944, all 18 lost their names and were redesignated PC-1586 through 1603.
Of the 11 Atlantic units, PC-1593- 1597 were sent to the Mediterranean, where they saw service during the landings in France in August 1944 and elsewhere as local escorts. They returned to Jacksonville, Florida, in June 1945, seeing no further action. PC-1598-1603 were dispatched to the Pacific in July 1944 and escorted support convoys as U.S. forces drew closer to the Japanese homeland. During the invasions at Okinawa and Iwo Jima, several were used as inshore control ships for landing craft, and two were further redesignated as control craft PCC-1599 and PCC-1601 in the summer of 1945. Only PC-1601 (ex-Fierce, AM-97) was lost during the war, on 21 May 1945. With the exception of the mothballed PC-1590 (ex- Constant, AM-86), which was recommissioned in May 1950 as a Naval Reserve training craft and served in that capacity until October 1954, the survivors were decommissioned quickly postwar and disposed of.
At 450 tons full load, the Adroit class displaced 18 tons more than did the PCs. All but the last four built were propelled by two 1,770 brake horsepower Cooper- Bessemer GNB-8 diesels; AM-96-99 were given 1,440 brake horsepower Busch- Sulzer BS 539 diesels, although the entire class was rated as able to achieve 16.8 knots at 330 tons displacement. They could at least nominally travel about 4,000 nautical miles at 12 knots, and the normal crew comprised 4 officers and 61 enlisted personnel.
The last of the Adroit-class minesweepers, the Force (AM-99), is seen in a builder’s trials photo five days before her commissioning on 16 May 1943. As completed, the Admits carried a 3-inch, 50-caliber Mk 22 dual-purpose gun forward and no main-deck gun aft; initially they were fitted with one 20-mm antiaircraft gun atop the pilothouse and two more abreast the mast, but later units received four 20-mm mounts. For antisubmarine duties, they were given two Mk 7 depth-charge racks.
With her new hull number already applied, the PC-1598 (ex-Excel, AM-94) displays the armament fitted to the Pacific units by Norfolk Navy Yard. Forward of the 3-inch gun are two 12-round Mk 22 Mousetrap antisubmarine rocket launchers, and two Mk 6 depth-charge mortars are mounted just abaft the newly installed 40-mm Mk 3 antiaircraft gun. The original Mk 7 depth-charge racks have been replaced with Mk 9s, with racks for reload charges fitted between them. The five 20-mm antiaircraft mounts are fitted two on the main deck aft, two abreast the foremast, and one atop the pilothouse. Note the crow’s nest lookout position still fitted on the mast.