Q-ship

Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open fire and sink them.

They were used by the British Royal Navy (RN) and the German Kaiserliche Marine during the First World War and by the RN, the Kriegsmarine and the United States Navy during the Second World War (1939–45).

In the 1670s, HMS Kingfisher (1675) was specially designed to counter the attacks of Algerine corsairs or pirates in the Mediterranean by masquerading as a merchantman, hiding her armament behind false bulkheads. She was also provided with various means of changing her appearance.

During the French Revolutionary Wars, a French brig disguised as a merchantman, with hidden guns and most of her crew below decks, was beaten off by the privateer lugger Vulture out of Jersey.

In the First Battle of the Atlantic, Britain was by 1915 in desperate need of a countermeasure against the U-boats that were strangling her sea-lanes. Convoys, which had proved effective in earlier times (and would again prove effective during the Second World War), were rejected by the resource-strapped Admiralty and the independent captains. Depth charges of the time were relatively primitive, and almost the only chance of sinking a submarine was by gunfire or by ramming while on the surface. The problem was how to lure the U-boat to the surface.

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