On board The Royal Naval Reserve coastal minesweeper Mersey (1957) during the NATO exercise Northern Merger in the North Sea off the Danish coast. The photographer is on the port side of the sweep deck abreast the minesweeping winch looking aft over the side showing a kite otter in the water with an Oropesa float astern of it while a sweep for moored influence mines is being undertaken. The Oropesa float marks the end of the sweep wire and the kite otter multiplane ensures that the wire remains at the correct depth. Another kite otter performs a similar function at the ship's end of the sweep wire.