An armed boarding steamer (or "armed boarding ship", or "armed boarding vessel") was a merchantman that the British Royal Navy converted to a warship during the First World War. AB steamers or vessels had the role of enforcing wartime blockades by intercepting and boarding foreign vessels. The boarding party would inspect the foreign ship to determine whether to detain the ship and send it into port or permit it to go on its way.
On 28 September 1914 Admiral John Jellicoe, commander-in-chief of the Grand Fleet, sent a telegram in which he pointed out that he did not have enough destroyers available to enforce the blockade. Furthermore, the weather was often too severe for the destroyers. Although Jellicoe did not mention it, after the loss on 22 September of the cruisers HMS Cressy, Aboukir and Hogue, he also did not want large warships making themselves sitting targets for submarines by stopping to examine merchant vessels.[1]
The first request was for 12 vessels, all to be capable of 12–14 knots (22–26 km/h; 14–16 mph), be able to carry enough coal for five days at sea, have wireless, and have boats suitable for boarding parties to use. Each armed boarding steamer was to carry two 3-pounder guns (47 mm/L50) and be under the command of an officer from the Royal Navy. These 12 vessels were requisitioned in October and completed by mid to late-November. Other vessels followed.[1]
The Navy found that cross-Channel passenger vessels were particularly suitable because of their large cargo capacity. As experience with the programme increased, the armed boarding vessels received heavier armament.[1] The Royal Navy realized the need for heavier armament after the German auxiliary cruiser SMS Meteor attacked and sank the armed boarding ship HMS Ramsey on 8 August 1915. The navy wanted to arm the boarding ships with some obsolete 14-inch torpedo tubes, and modern 4-inch (100 mm) guns (possibly the BL 4-inch Mk VII naval gun); Meteor had sunk Ramsey using both a torpedo, and gunfire from two 88 mm (3.5-inch) guns.[a]
The Navy pressed the vessels into other roles. Some carried depth charges for anti-submarine duty while escorting convoys. Still others, particularly in the Mediterranean, served as transports.[citation needed] A quarter were lost during active duty in the war; eight sunk by submarines, one by a German auxiliary cruiser, and one by mines. Two went on to serve again in WWII, with one then being lost to bombing.[citation needed]
HMS Fiona – Wrecked 6 September 1917 on the Pentland Skerries
HMS Grangemouth – Launched 1898; ABS from 5 January 1915 to 1 April 1919
HMS Grive – Launched 1905; hired as a store carrier 5 August 1914 and ABS from 14 February 1916. Torpedoed by UC-40 on 8 December 1917 in the North Sea off Lerwick;[6] foundered 24 December.
HMS Hazel – Launched 1907; ABS from 14 November 1914 to 17 February 1919
HMS Heroic – Launched 1906; ABS from 18 November 1914 to 6 July 1920; troop transport July 1917 to January 1918.
HMS Lama – Launched 1905; ABS from 12 July 1915 to 17 January 1918
HMS Louvain – sunk by torpedo by SM UC-22 on 20 January 1918 while in the Kelos strait in the Aegean Sea; seven officers and 217 men killed; 17 survivors.[8]
HMS Lunka – Launched 1905; ABS from 20 July 1915 to 22 January 1919
HMS Partridge – Launched 1906. ABS from 15 November 1914. Action with a U-boat on 15 March 1915. HMS Partridge (II) from 1916 to 12 July 1920.
HMS Vienna – Launched 1894; Accommodation ship from 21 August 1914 to December, then decoy shipAntwerp from 1 January 1915 to 28 April 1915, and lastly ABS from 29 March 1915 to 25 August 1919.
HMS Woodnut – Launched 1906 as Woodcock; ABS from 15 November 1914 to 31 March 1920
HMS York – Launched 1907; ABS 3 January 1915 to 4 April 1919.
^Helgason, Guðmundur. "Ships hit during WWI: Sarnia". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 17 October 2012.