Ocean boarding vessel
Ocean boarding vessels were merchant ships taken over by the Royal Navy for the purpose of enforcing wartime blockades by intercepting and boarding foreign vessels.
Ships
| Ship | Date launched/ completed | Date requisitioned/ commissioned | History |
| 1926 | Converted to "Catapult Armed Ship". Used for convoy escort | ||
| HMS Empire Audacity | 29 Mar 1939 | 11 Nov 1940 | Former German ship Hannover captured 7/8 March 1940 and put into British service. Commissioned as Ocean boarding vessel in November 1940 but sent for conversion to escort aircraft carrier in January 1941. |
| June 1915 | 26 Sep 1940 | Torpedoed and sunk 6 May 1941 | |
| Rescued survivors of Oct 1942 Rescued survivors of 14 March 1943. | |||
| 1935 | Aug 1940 | Sunk 4 Feb 1941 after torpedo attack previous day | |
| 28 September 1925 | August 1940 | The cross channel steamer was requisitioned by the Admiralty as a Barrage Balloon Vessel, converted to Ocean Boarding Vessel in 1943. She was sunk off Normandy by a Neger manned torpedo 18 August 1944. | |
| 17 Apr 1931 | 21 Jan 1941 | Former SS Hilary; restored as a merchantman 15 April 1942; recommissioned as an infantry landing and headquarters ship 1943; returned to civilian service after the war in 1945; scrapped 1959. | |
| 1925 | 11 August 1940 | Bombed and sunk on 7 September 1940. Salvaged and converted to cargo ship Empire Explorer, never saw service as an ocean boarding vessel. Torpedoed and sunk in July 1942. | |
| 1937 | 11 August 1940 | Bombed and sunk on 7 September 1940. Salvaged and converted to cargo ship Empire Chivalry, never saw service as an ocean boarding vessel. Sold postwar and renamed Planter. Scrapped 1958. | |
| 1929 | Requisitioned by Admiralty in 1940. Sunk by Italian submarine in N Atlantic, 15 July 1941. | ||
| 1938 | 1941 | French ship MV Charles Plumier in 1938; seized by Royal Navy; returned to France 1945; sold to a Greek company and renamed MV Pleias 1964; scrapped 1968 | |
| 1937 | abandoned after being bombed, North Atlantic, 19 July 1941 | ||
| 1920 | 1940 | sailed with Arctic convoy OB 288 and sunk 24 February 1941, no survivors | |
| Participated in locating German supply ships after Bismarck had been sunk | |||
| 1932 | Formerly Erin. Converted to Fighter catapult ship 1940. | ||
| 1922 | converted to Fighter catapult ship in 1940. Sank after attacked by German aircraft 1941 | ||
| 1930 | 13 Sep 1940 | Bombed off Cape Cornwall 27 May 1941; repaired and returned to merchant use Nov 1941; sunk 29 Sep 1942 |