SM U-158 was a Type U-158 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 of the Kaiserliche Marine

Kaiserliche Marine

The Imperial German Navy was the German Navy created at the time of the formation of the German Empire. It existed between 1871 and 1919, growing out of the small Prussian Navy and Norddeutsche Bundesmarine, which primarily had the mission of coastal defense. Kaiser Wilhelm II greatly expanded...

, built during the First World War

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

.

SM U-158 was one of six 810-ton boats ordered in February 1917. She was one of two ships built to an improved design developed from the Type U-115 design, along with her sister, SM U-159

SM U-159

SM U-159 was a Type U-158 submarine of the Kaiserliche Marine, built during the First World War.SM U-159 was one of six 810-ton boats ordered in February 1917. She was one of two ships built to an improved design developed from the Type U-115 design, along with her sister, SM U-158. They were...

. They were known as 'Project 25', and had a greatly increased radius of action. Both ships were built at Kaiserliche Werft Danzig

Kaiserliche Werft Danzig

Kaiserliche Werft Danzig was a German shipbuilding company founded in 1852, first as Königliche Werft Danzig but renamed in 1871 with the proclamation of the German Empire. Together with Kaiserliche Werft Kiel and Kaiserliche Werft Wilhelmshaven it was one of three shipyards which produced...

, with U-158 being launched on 16 April 1918. The war ended before she could see active service, and she was broken up in 1919.