North Sea Mine Barrage - Cleanup

Cleanup

United States participation in the minesweeping effort was overseen by Rear Admiral Strauss aboard the repair ship Blackhawk from which he had commanded the minelaying operation. Tugs Patapsco and Patuxent towed Admiralty wooden sailing smacks Red Rose and Red Fern out to conduct the first trial sweep in December. Sweeping was accomplished by suspending a serrated wire between two ships on a parallel course. While held underwater by planing devices called "kites", the wire would foul the cables suspending the buoyant mines above their anchors. If the serrated wire parted the mine mooring cable, the mine would bob to the surface to be destroyed by gunfire. The smacks swept and destroyed six mines before winter weather halted further work at sea. The winter was spent testing an electrical protective device to reduce the risk of sweeping the antenna mines with steel-hulled ships. Patapsco and Patuxent tested the protective device by sweeping 39 mines in March. Royal Navy minesweeping efforts involved 421 vessels manned by 600 officers and 15,000 men from 1 April to 30 November 1919.

Twelve Lapwing class minesweepers and 18 submarine chasers were available for the first routine sweep of the United States minesweepers on 29 April 1919. After the first sweep took two days to clear 221 mines, Strauss requested more ships in the hope of clearing the mine barrage that summer. Twenty Admiralty trawlers with American crews, 16 more Lapwing class minesweepers, and another repair ship Panther were assigned to his command. Panther was given responsibility for tending trawlers William Ashton, Thomas Blackhorne, Thomas Buckley, Richard Bulkeley, George Burton, Pat Caharty, William Caldwell, George Clarke, John Clay, George Cochrane, John Collins, William Darnold, Sam Duffy, John Dunkin, John Fitzgerald, John Graham, Thomas Graham, Thomas Henrix, William Johnson, Thomas Laundry, and submarine chasers SC-37, 38, 40, 44, 45, 46, 47, 48, 95, 110, 164, 178, 181, 182, 206, 207, 208, 254, 256, 259, 272, 329, 354 and 356. Blackhawk provided tender services for the larger ships operating as six divisions.

• Mine Division 1: Turkey, Robin, Quail, Kingfisher, Finch, Falcon
• Mine Division 2: Eider, Pelican, Bobolink, Woodcock, Rail, Teal, Seagull, Swallow
• Mine Division 3: Oriole, Auk, Heron, Sanderling, Chewink, Tanager
• Mine Division 4: Thrush, Avocet, Grebe, Curlew, Cormorant, Mallard
• Mine Division 5: Lark, Swan, Widgeon, Whippoorwill, Flamingo
• Buoying Division: Osprey, Patapsco, Patuxent, Lapwing, Penguin

Common difficulties with the sweeping procedure involved mine cables becoming entangled in the kites attached to the sweeping wires. Sweeping gear was often lost if the mine detonated and cut the sweeping cables. Approximately one third of the ships were damaged by exploding mines. Two men were killed in separate incidents while attempting to haul mines aboard to clear fouled sweeping kites. It had been assumed the Mk 6 mine hydrostatic safety devices would minimize the risks of this procedure, but sweeping gear losses increased after unreliability of these safety devices was recognized. Countermining sequences initiated by destruction of a swept mine causing detonation of an undetected mine closer to one of the minesweepers were another source of damage. Some of this countermining was attributed to acceleration of the antenna fuze relay armature or seawater leaking into damaged mines rather than sympathetic detonation of explosives. The minesweepers were sometimes able to continue sweeping, but the trawlers were less durable. Seven men drowned when the Richard Bulkeley was sunk by a mine detonation on 12 July. Strauss discontinued use of the trawlers for minesweeping, but retained six for transporting replacement sweeping gear to minesweepers when wires were destroyed by exploding mines. The remaining 13 trawlers were returned to the Admiralty. Most damaged ships were repaired, but SC-38 was declared a total loss. Three more men of the minesweeping force were killed in individual accidents involving sweeping gear before Strauss declared the barrage cleared on 30 September 1919. The minesweepers found only about 25 to 30 percent of the mines laid a year earlier; but it was assumed the others had either broken free, sunk to the bottom, or been destroyed by premature explosions. Strauss was recognized as a Knight Commander of St Michael and St George for his efforts; but doubts about effectiveness of the minesweeping effort persisted into the 21st century.