SM U-55

U-55 was ordered from Germaniawerft, Kiel on 23 August 1914, was laid down on 28 December 1914 and launched on 18 March 1916. She was commissioned under her first commander Wilhelm Werner on 8 June 1916.

Werner commanded her for most of her wartime career, during which she undertook 14 patrols with II Flotilla, sinking 64 ships for a total of 130,387 GRT. She also damaged another five for a total of 25,568 gross register tons (GRT), and took another two as prizes for a total of 4,616 GRT. Her most famous act was the sinking of the British passenger liner RMS Carpathia with three torpedoes, on 17 July 1918, off the east coast of Ireland. Carpathia herself had become famous for her actions in coming to the rescue of the sinking RMS Titanic in 1912. U-55 also sank the hospital ship HMHS Rewa on 4 January 1918.

Werner was replaced by Alexander Weiss on 10 August 1918, Weiss being succeeded by Hans Friedrich on 15 September and commanding U-55 until the armistice on 11 November.

On 26 November 1918 U-55 was surrendered to the Royal Navy at Harwich, along with the rest of the surviving U-Boat fleet. It was subsequently handed over to Japan, and entered service with the Imperial Japanese Navy in 1920 as O3, serving as such until 1921.[6] It was dismantled at the Sasebo Navy Yard between March and June 1921, briefly recommissioning in 1923 as Auxiliary Vessel No. 2538.

• Room 40

• Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
• Spindler, Arno (1966) [1932]. Der Handelskrieg mit U-Booten. 5 Vols. Berlin: Mittler & Sohn. Vols. 4+5, dealing with 1917+18, are very hard to find: Guildhall Library, London, has them all, also Vol. 1-3 in an English translation: The submarine war against commerce.
• Beesly, Patrick (1982). Room 40: British Naval Intelligence 1914-1918. London: H Hamilton. ISBN 978-0-241-10864-2.
• Halpern, Paul G. (1995). A Naval History of World War I. New York: Routledge. ISBN 978-1-85728-498-0.
• Roessler, Eberhard (1997). Die Unterseeboote der Kaiserlichen Marine. Bonn: Bernard & Graefe. ISBN 978-3-7637-5963-7.
• Schroeder, Joachim (2002). Die U-Boote des Kaisers. Bonn: Bernard & Graefe. ISBN 978-3-7637-6235-4.
• Koerver, Hans Joachim (2008). Room 40: German Naval Warfare 1914-1918. Vol I., The Fleet in Action. Steinbach: LIS Reinisch. ISBN 978-3-902433-76-3.
• Koerver, Hans Joachim (2009). Room 40: German Naval Warfare 1914-1918. Vol II., The Fleet in Being. Steinbach: LIS Reinisch. ISBN 978-3-902433-77-0.

• Photos of cruises of German submarine U-54 in 1916-1918. Great photo quality, comments in German.
• A 44 min. film from 1917 about a cruise of the German submarine U-35. A German propaganda film without dead or wounded; many details about submarine warfare in World War I.
• Helgason, Guðmundur. "WWI U-boats: U-55". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net.
• Room 40: original documents, photos and maps about World War I German submarine warfare and British Room 40 Intelligence from The National Archives, Kew, Richmond, UK.