SM U-55

SM U-55 was one of the six Type U-51 U-boats of the Imperial German Navy during the First World War.

Construction and commissioning
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.

In German service
Werner commanded her for most of her wartime career, during which she undertook 14 patrols with II Flotilla, sinking 61 merchant ships for a total of. She also damaged another seven for a total of, and took another two as prizes for a total of 3,466 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 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 1918.

In Japanese service
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 O-3, serving as such until 1921. It was dismantled at the Sasebo Navy Yard between March and June 1921, briefly recommissioning in 1923 as Auxiliary Vessel No. 2538.