SM UB-23 was a German Type UB II

German type UB II submarine

The UB II type submarine was a class of U-boat built during World War I by the Kaiserliche Marine. They were enlarged from the preceding type UB I and were more effective vessels. The boats were a single hull design with a 50 metre maximum diving depth and a 30-45 second diving time...

 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...

 or U-boat

U-boat

U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

 in the German Imperial Navy  during World War I

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...

. The U-boat was ordered on 30 April 1915 and launched on 9 October 1915. She was commissioned into the German Imperial Navy on 11 March 1916 as SM UB-23."SM" stands for "Seiner Majestät" (His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine. The submarine sank 52 ships in 21 patrols. UB-23 was badly damaged by a depth charge

Depth charge

A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

 attack by off the Lizard

The Lizard

The Lizard is a peninsula in south Cornwall, England, United Kingdom. The most southerly point of the British mainland is near Lizard Point at ....

. UB-23 put in at Corunna

A Coruña

A Coruña or La Coruña is a city and municipality of Galicia, Spain. It is the second-largest city in the autonomous community and seventeenth overall in the country...

, Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

, and was interned.