A Fleet of Mines. Steam winches are used to haul trains or fleets of 20 to 40 mines each, aft to the feeding section. There the mines are seized by gangs of 4 men, who push each mine in turn up to the trap at the stern of the ship. Each time the trap is released to go overboard. Above the mines is seen a marker buoy used by the mine squadron to mark the end of a mine field when it was intended to resume that line on a subsequent expedition. North Sea.
Naval History and Heritage Command