Submarine Chaser 173' Steel Hull
Early PC's were converted yachts acquired by the Navy. These together with the 362 World War II built PCs replaced the larger and more valuable DD's and DE's around harbours and restricted waters. The 173 foot World War II constructed PC was steel hulled, twin diesel propelled and armed with a dual-purpose 3"/50 and 40mm gun. Later the 3"/50 was replaced with a single Bofors 40mm and three single 20mm guns were added. PCs carried a considerable amount of detection and ranging gear for locating submarines. They were capable of a speed of about 18 knots and were highly manoeuvrable. The Steel-hulled PC-461 Class ships were built in three series; PC-461 to PC-496 (36), PC-542 to PC-627 (86), PC-776 to PC-826 (51), PC-1077 to PC-1265 (189). Some PCs were converted to Amphibious Control Vessels and reclassified PCC.
In addition to 403 173-foot PC-class patrol craft ordered for the U.S. Navy in 1941, eighteen 173-foot hulls were ordered for use as minesweepers, as the Adroit class. Built by five yards, all but three of the mine craft 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 stem, 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 stem 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 to 93) or from mainland U.S. bases, again as convoy escorts. That they were far more useful in an antisubmarine role than as mine craft 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 Harbour. On 1 June 1944, all 18 lost their names and were reclassified 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 lwo Jima, several were used as inshore control ships for landing craft, and two were further reclassified 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 post-war 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 four officers and 61 enlisted personnel