Q-ships also known as Q-boats, Decoy Vessels, Special Service Ships or Mystery Ships were heavily armed merchant ships which were intended to lure submarines into surface attacks, in order to sink them.
They were used by the British Royal Navy (RN) during World War I and by both the RN and the United States Navy during the Second World War (1939–1945), as a countermeasure against German U-boats and Japanese submarines.
One solution to this problem was the creation of the Q-ship, one of the most closely-guarded secrets of the war. Their codename referred to the vessels' home port, Queenstown, in Ireland. These would be known to the Germans as a U-Boot-Falle ("U-boat trap"). The Q-ship would pose as an easy target for the U-boat but in fact carry hidden armament. A typical Q-ship would be an old-looking tramp steamer calmly sailing alone near an area where a U-boat was reported to be operating. By posing as a suitable target for the use of the U-boat's deck gun, the Q-ship would encourage the U-boat captain to bring his vessel to the surface rather than use one of his expensive torpedoes, which were in short supply. The cargoes of the Q-ships would be wooden caskets and wood (e.g., balsa or cork) so even if torpedoed they would stay afloat, encouraging the U-boat to surface and use its gun. If necessary the crew could even stage an "abandon ship" routine. Once the U boat was in a suitable position the Q-ship would change rapidly, false panels would drop to reveal the hidden guns which would start firing. At the same time the White Ensign (Royal Navy flag) would be raised. With the element of surprise the U-boat could be quickly overwhelmed.
The first victory of a Q-ship occurred on June 23, 1915, when U-40 was sunk near Aberdeen by the submarine HMS C24, cooperating with the decoy vessel Taranaki, commanded by Lieutenant Frederick Henry Taylor CBE DSC RN. In August of that year, an even smaller converted fishing trawler named His Majesty's Armed Smack Inverlyon successfully destroyed UB-4 near Great Yarmouth. The Inverlyon was an unpowered sailing craft fitted with a small 3 pounder (47 mm) gun. The British crew put 9 rounds from the 3 pounder and small arms fire into U-4 at close range sinking her with the loss of all 15 crew, despite the attempt of the Inverlyon's skipper to rescue one German submariner.
On August 19, 1915, Lieutenant Godfrey Herbert RN of the HMS Baralong sank U-27 which had been preparing to sink a nearby transport ship. About a dozen of the sailors survived and swam towards the merchantman; Herbert, fearing that they would scuttle her, ordered them to be shot at as they swam towards the transport and sent a boarding party which killed the German sailors who reached her; this became known as the "Baralong Incident".
Lieutenant-Commander William Edward Sanders VC, DSO, a New Zealander commanding HMS Prize, won the Victoria Cross for an action on 30 April, 1917 with U-93, which was severely damaged. Sanders waited, while his ship sustained heavy shellfire, until the submarine was within 80 yards, whereupon the White Ensign was hoisted and the Prize opened fire. The submarine appeared to sink. Unbeknownst to Sanders, the submarine did not sink and struggled back to port. With his ship identified by the survivors of U-93, Sanders and his crew were killed when they were attacked by U-43 on 14 August 1917.
In the course of 150 engagements they destroyed 14 U-boats and damaged 60, at a cost of 27 Q-ships lost out of 200. Q-ships were responsible for only about 10% of all U-boats sunk, ranking them far below the use of mine fields in overall effectiveness. Neither of the German Q-Boats, Möwe and Wolf, had any success in destroying enemy submarines.
Nine Q-Ships were commissioned by the Royal Navy in September and October 1939 for work in the North Atlantic:
Prunella and Edgehill were torpedoed and sunk 21 and 29 June 1940 without even sighting a U-Boat. The rest of the vessels were paid off in March 1941 without successfully accomplishing any mission.
The last Royal Navy Q-ship, 2456-ton HMS Fidelity (D57), was converted in September, 1940, to carry a torpedo defense net, four 4-inch (10-cm) guns, four torpedo tubes, two OS2U Kingfisher float planes, and Motor Torpedo Boat 105. Fidelity sailed with a French crew, and was sunk by U-435 on 30 December 1942 during the battle for Convoy ON-154.
By January 12, 1942, the British Admiralty's intelligence community had noted a "heavy concentration" of U-boats off the "North American seaboard from New York to Cape Race" and passed along this fact to the United States Navy. That day, U-123 under Kapitänleutnant Reinhard Hardegen, torpedoed and sank the British steamship Cyclops, inaugurating Paukenschlag (literally, "a roll on the kettledrum" and sometimes referred to in English as "Operation Drumbeat"). U-boat commanders found peacetime conditions prevailing along the coast: towns and cities were not blacked-out and navigational buoys remained lighted; shipping followed normal routines and "carried the normal lights." Paukenschlag had caught the United States unaware.
Losses mounted rapidly. On January 20, 1942, Commander-in-Chief, United States Fleet (Cominch), sent a coded dispatch to Commander, Eastern Sea Frontier (CESF), requesting immediate consideration of the manning and fitting-out of "Queen" ships to be operated as an antisubmarine measure. The result was "Project LQ."
Five vessels were acquired and converted secretly in Portsmouth, New Hampshire:
The careers of all five ships were almost entirely unsuccessful and very short, with USS Atik sunk on its first patrol; all Q-ships patrols ended in 1943.
American Q-ships also operated in the Pacific Ocean. One was USS Anacapa (AG-49) formerly the lumber transport Coos Bay which was converted to Q-ship duty as project "Love William." Anacapa was not successful in engaging any enemy submarines, although she is believed to have damaged two friendly subs with depth charges when they were improperly operating in her vicinity. Anacapa was also withdrawn from Q-ship duty in 1943 and served out the remainder of WWII as an armed transport in the South Pacific and Aleutian Islands.
The term (or "Q-car") has subsequently been used to describe cars that have much higher than average performance (often through extensive modification) but look like conventional, uninteresting family transport. As well as the ships, this term may also be reinforced by the United Kingdom's system of vehicle registration plate numbering - until recent years the first (previously the last) symbol on a British plate was a letter code for the year of manufacture, but for vehicles of uncertain or mixed age, a plate beginning with "Q" is used.
The Q-ship concept is also used by science fiction author David Weber in his Honor Harrington books, most notably in "Honor Among Enemies."