(Tr: t. 290; l. 125'5"; b. 23'5"; dph. 12'7"; s. 10 k.; cpl. 16; a. rifles; cl. "Castle")
William Darnold—a steel-hulled, screw steam trawler built in 1918 at Beverley, England, by Cook, Welton, and Gemmell, Ltd., for the British Admiralty—was leased by the United States Navy in the spring of 1919 for service sweeping the North Sea Mine Barrage and was commissioned on 30 May 1919 at Grimsby, England, Lt. Edmond Delany in command.
William Darnold—assigned to the 2d Trawler Division, Minesweeping Detachment, North Atlantic Fleet —got underway on 31 May for the Orkney Islands, in company with four other trawlers. She arrived at Kirkwall, Scotland—the base of the Minesweeping Detachment—on 2 June. She remained there until 16 June, when she shifted briefly to Ottswick. While returning to Kirkwall two days later, William Darnold came across a drifting mine and destroyed it with small arms fire.
After spending a week in local operations out of Kirkwall, streaming sweep wire daily to give her winchman experience in operating the ship's winch, William Darnold sailed for the minefields on 7 July to participate in the fourth minesweeping operation undertaken by the Minesweeping Detachment. The tactics employed in the operation involved two-ship sweeps in which a wire was streamed between two minecraft to catch a mine and detonate it or cut it adrift so that it could be exploded with rifle fire. Often, the gear—whether it was a "kite," or "otter," or the wire itself—would become damaged. Repair or replacement of the damaged gear had to be effected to enable the operations to resume.
Operating together on 9 July, William Darnold and John Graham exploded 22 mines and cut adrift 15 more which were sunk or detonated by gunfire during the day's operations. At 1530, a jarring blast shook William Darnold, when a mine—set off by the explosions of four others which she had exploded at that time— exploded beneath the ship's port side, damaging her hull and machinery and causing her to be towed to the anchorage for the night.
During the evening hours, William Darnold's crew effected the necessary repairs, enabling the ship to resume operations the next morning, 10 July. Over the next two days, the trawler worked in the minefield, conducting her sweep operations. On 12 July, the trawler Richard Bulkeley accidentally exploded a mine close aboard; the ship sank in four minutes, taking seven men—including Comdr. Frank L. King, the commander of the trawler division—down with her.
William Darnold cut her own wire and proceeded to the scene of the disaster, lowering a boat and searching for survivors. Eventually, Richard Bulkeley's survivors were picked up by other vessels in the vicinity.
Returning to Kirkwall on 13 July, William Darnold moored alongside Prometheus (Repair Ship No. 3) for "urgent repairs." The trawler then spent the next three weeks awaiting further orders before getting underway for Brightlingsea, England, on 5 August. Touching at Inverness, Scotland, en route, William Darnold slightly damaged the entrance lock to the Caledonian Canal during the transit of 5 August.
Making port at Brightlingsea on 10 August, the trawler moored near Chattanooga (Cruiser No. 16) to transfer commissary supplies before receiving an inspection from British naval authorities. The following day, on 11 August 1919, William Darnold was decommissioned and returned to the British Admiralty.