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. The use of Q-ships contributed to the abandonment of cruiser rules restricting attacks on unarmed merchant ships and to the shift to unrestricted submarine warfare in the 20th century.
HMS Umbra (P35) was a Royal Navy U-class submarine built by Vickers-Armstrongs at Barrow-in-Furness. So far she has been the only ship of the Royal Navy to bear the name Umbra.
HMS Safari was a third batch S-class submarine built for the Royal Navy during World War II. Commissioned in 1942, she was assigned to operate in the Mediterranean Sea. During the course of the war, Safari sank twenty-five ships, most of which were Italian.
HMS Splendid was a third-batch S-class submarine built for the Royal Navy during World War II. She was laid down on 7 March 1941 and launched on 19 January 1942. After an initial patrol through the Bay of Biscay to Gibraltar, Splendid conducted two patrols in the Mediterranean Sea; one was abandoned after technical problems and on the other she sank two Italian ships. On her next patrol, the submarine attacked two Italian convoys, sinking an Italian destroyer in the second attack. Based in Algiers, the boat operated north of Sicily, sinking six Italian ships, including two tankers and two heavy merchant ships. Splendid was detected by a German destroyer on 21 April 1943 while patrolling off Naples, Italy; the submarine was attacked with depth charges by the destroyer and forced to surface, after which she was scuttled and her surviving crew members taken prisoner. She was the most successful British submarine by tonnage sunk between November 1942 and May 1943.
HMS Sickle was a third-batch S-class submarine built for the Royal Navy during World War II. Completed in 1942, she made her initial war patrol off the Norwegian coast. Sickle then sailed to Gibraltar, from where she conducted one patrol, then to Algiers, French North Africa. From 10 May to 10 October, the boat patrolled the Gulf of Genoa five times and sank a German submarine as well as three minesweepers and an escort ship. She then moved to Beirut, French Lebanon, and conducted two patrols in the Aegean Sea, sinking three caïques and a merchant ship, in addition to landing resistance operatives in Greece.
HMS Simoom was a third-batch S-class submarine built for the Royal Navy during World War II. She was laid down on 14 July 1941 and launched on 12 October 1942.
HMS Sahib was a third-batch S-class submarine built for the Royal Navy during the Second World War. She was launched on 19 January 1942 and commissioned on 13 May 1942. She was the only British naval vessel to bear the name Sahib.
HMS Sportsman was a third-batch S-class submarine built for the Royal Navy during World War II. Completed in 1942, she spent most of the war serving in the Mediterranean Sea. After an initial patrol off Norway, she sank the heavy transport Général Bonaparte in the Mediterranean in 1943 and missed a French oil tanker. She was heavily damaged after a mistaken attack by an Allied bomber, and was sent east after repairs to participate in operations in the Black Sea. After the operation was cancelled, Sportsman patrolled the Aegean Sea, sending several Greek and German ships to the bottom. She sank the German transport SS Petrella in early 1944 despite it being clearly marked as a prisoner-of-war ship, killing 2,670 out of 3,173 Italians aboard. Sportsman sank several more ships, and suffered minor damage when she was detected and sighted while attempting to attack a convoy.
HMS Porpoise (N14) was one of the six-ship class of Grampus-class mine-laying submarines of the Royal Navy. She was built at Vickers Armstrong, Barrow and launched 30 August 1932. She served in World War II in most of the naval theatres of the war, in home waters, the Mediterranean and the Far East. She was sunk with all hands by Japanese aircraft on 19 January 1945, and was the last Royal Navy submarine to be lost to enemy action.
HMS Rorqual (N74) was a British mine-laying submarine, one of the six ships of the Grampus class of the Royal Navy. She was built by Vickers Armstrong, Barrow and launched 27 July 1936. She served in the Second World War in the Mediterranean and in the far east. She was the only Grampus-class submarine to survive the war, and she is considered the most successful minelaying submarine of World War II, sinking 57,704 GRT of enemy shipping, 35,951 of which through her mines.
HMS Torbay (N79) was a T-class submarine of the Royal Navy. She was laid down at Chatham Dockyard and launched on 9 April 1940.
HMS Turbulent (N98) was a T-class submarine of the Royal Navy. She was laid down by Vickers Armstrong, Barrow and launched in May 1941.
HMS Ursula was a U-class submarine, of the first group of that class constructed for the Royal Navy. The submarine entered service in 1938 and saw action during the Second World War in the North and Mediterranean Seas. In 1944, Ursula was transferred to the Soviet Navy and renamed V-4. She remained in Soviet service until 1950 when the submarine was returned to the United Kingdom and was sold for scrap in May 1950.
HMS Utmost was a British U class submarine, of the second group of that class, built by Vickers Armstrong, Barrow-in-Furness. She was laid down on 2 November 1939 and was commissioned on 17 August 1940. So far she has been the only ship of the Royal Navy to bear the name Utmost.
HMS Ultor (P53) was a Royal Navy U-class submarine built by Vickers-Armstrong at Barrow-in-Furness, launched in 1942, and part of the third group of the class. So far she has been the only ship of the Royal Navy to bear the name Ultor.
HMS Unruffled was a Royal Navy U-class submarine built by Vickers-Armstrong at Barrow-in-Furness. So far she has been the only ship of the Royal Navy to bear the name Unruffled.
HMS Unruly was a Royal Navy U-class submarine built by Vickers-Armstrong at Barrow-in-Furness. So far she has been the only ship of the Royal Navy to bear the name Unruly.
HMS Unshaken (P54) was a Royal Navy U-class submarine built by Vickers-Armstrong at Barrow-in-Furness. She has been the only vessel of the Royal Navy to bear the name Unshaken.
HMS Uproar (P31) was a Royal Navy U-class submarine built by Vickers-Armstrong at Barrow-in-Furness. So far she has been the only ship of the Royal Navy to bear the name Uproar. She was originally named P 31, renamed Ullswater in February 1943 and finally renamed Uproar in April 1943.
Pegaso was a torpedo boat and an escort aviso of the Italian Regia Marina. She was one of the most successful Axis anti-submarine warships of World War II.
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