sperrbrecher

A Sperrbrecher (German; informally translated as "pathfinder" but literally meaning "mine barrage breaker"), was a German auxiliary ship of the First World War and the Second World War that served as a type of minesweeper, steaming ahead of other vessels through minefields and detonating them with its reinforced hull. Also used as anti-aircraft ships, the Sperrbrecher suffered heavy losses in the war.

==Background== The advent of the naval mine in the late 19th century created a new hazard for shipping in time of war. The flexibility and cost-effectiveness of mines made them attractive to belligerents as both a defensive and an offensive measure. The cost of producing and laying a minefield was far less than the cost of clearing it, and it can take up to 200 times as long to clear a minefield as to lay it. Furthermore, offensive mine fields laid in an enemies harbours or trade routes can paralyze traffic until they are cleared, even if few ships are sunk or damaged, while moving valuable ships can involve a major sweeping operation ahead of its movement. Part of this effort is identifying where the mines are, which is sometimes only revealed when a ship runs into one.