<P> 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 . </P> <P> 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). </P> <P> 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 . </P> <P> 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 . </P>

Heavily armed decoy vessels used by the british during the first world war