SM U-28 was a Type U 27 U-boat that served in the First World War. It conducted 5 patrols, sinking 40 ships totalling 90,126 GRT.
SM U-110 was a Type U 93 U-boat of the German Imperial Navy during World War I. She was ordered on 5 May 1916 and launched on 28 July 1917. She was commissioned on 25 September 1917 as SM U-110. and assigned to IV Flotilla of the High Seas Fleet, based on the German North Sea coast.
SM UB-12 was a German Type UB I submarine or U-boat in the German Imperial Navy during World War I. The submarine disappeared in August 1918.
SM UC-4 was a German Type UC I minelayer submarine or U-boat in the German Imperial Navy during World War I. The U-boat had been ordered by November 1914 and was launched on 6 June 1915. She was commissioned into the German Imperial Navy on 10 June 1915 as SM UC-4. Mines laid by UC-4 in her 73 patrols were credited with sinking 36 ships. UC-4 was scuttled off the coast of Flanders during the German evacuation on 5 October 1918.
SM UB-21 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 26 September 1915. She was commissioned into the German Imperial Navy on 20 February 1916 as SM UB-21. The submarine sank 33 ships in 26 patrols for a total of 36,764 gross register tons (GRT). Surrendered to Britain in accordance with the requirements of the Armistice with Germany, UB-21 was sunk as a target by HMS Terror in the Solent on 30 September 1920; the wreck was sold in 1970 and most had been cleared by 1998, although some remnants survive.
SM UB-23 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 9 October 1915. She was commissioned into the Imperial German Navy on 13 March 1916 as SM UB-23. The submarine sank 51 ships in 21 patrols for a total of 33,880 gross register tons (GRT). On 26 July 1917, UB-23 was badly damaged by a depth charge attack by HMS PC-60 off the Lizard; she put in at Corunna, Spain, on 29 July 1917 and was interned. On 22 January 1919 she was surrendered to France in accordance with the requirements of the Armistice with Germany, and she was broken up in Cherbourg in July 1921.
SM UC-17 was a German Type UC II minelaying submarine or U-boat in the Imperial German Navy in World War I. She was ordered on 29 August 1915 and launched on 29 February 1916. She was commissioned into the Imperial German Navy on 21 July 1916 as SM UC-17.
SM UC-71 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 12 January 1916 and was launched on 12 August 1916. She was commissioned into the German Imperial Navy on 28 November 1916 as SM UC-71. In 19 patrols UC-71 was credited with sinking 63 ships, either by torpedo or by mines laid. UC-71 sank on 20 February 1919 in the North Sea while on her way to be surrendered. Discovery a century later of her wreck with all hatches open suggested she had been deliberately scuttled by her own crew.
SM U-47 was a Type U-43 submarine of the Imperial German Navy. She engaged in commerce raiding during the First World War.
SM U-57 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-57 was engaged in naval warfare and took part in the First Battle of the Atlantic.
SM U-58 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-58 was engaged in the naval warfare and took part in the First Battle of the Atlantic.
SM U-60 was a German Type UB III submarine of the Imperial German Navy in the First World War. She took part in the First Battle of the Atlantic.
SM U-63 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-63 was engaged in naval warfare and took part in the First Battle of the Atlantic.
SM U-65 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-65 was engaged in the naval warfare and took part in the First Battle of the Atlantic.
SM U-73 was one of 329 submarines serving in the Imperial German Navy in World War I. She engaged in the commerce war as part of the First Battle of the Atlantic. U-73 has the distinction of being responsible for planting the underwater mine that later led to the sinking of the largest ship sunk during World War I, the 48,158 tons hospital ship Britannic.
SM U-14 was one of the 329 submarines serving in the Imperial German Navy in World War I.
SM U-22 was one of 329 submarines serving in the Imperial German Navy in World War I. U-22 was engaged in commerce war as part of the naval warfare, during the First Battle of the Atlantic.
SM U-24 was one of 329 submarines serving in the Imperial German Navy in World War I. She was engaged in commerce warfare during the First Battle of the Atlantic.
SM U-52 was one of 329 submarines serving in the Imperial German Navy in World War I. U-52 was engaged in the naval warfare and took part in the First Battle of the Atlantic.
SM UB-64 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the German Imperial Navy on 5 August 1917 as SM UB-64.
German Empire 
