SM UC-12 was a German Type UC I

German Type UC I submarine

The Type UC I submarines were a class of small coastal minelaying U-boats built in Germany during the early part of World War I. They were the first operational minelaying submarines in the world . A total of fifteen boats were built...

 minelayer

Minelayer

Minelaying is the act of deploying explosive mines. Historically this has been carried out by ships, submarines and aircraft. Additionally, since World War I the term minelayer refers specifically to a naval ship used for deploying naval mines...

 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...

.

Construction

The U-boat was ordered on 23 November 1914, laid down on 27 January 1915, and was launched on 29 April 1915. She was commissioned into the German Imperial Navy on 2 May 1915 as SM UC-12."SM" stands for "Seiner Majestät" (His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.

Service history

UC-12 served with the Pola Flotilla

Pola Flotilla

The Pola flotilla was an Imperial German Navy formation set up to prosecute the U-boat campaign against Allied shipping in the Mediterranean during the First World War in support of Germany’s ally, the Austro-Hungarian Empire...

 based at Cattaro in the Adriatic. She operated as a minelayer, and undertook seven patrols in this role. Mines laid by UC-12 were credited with sinking six ships. One of these, the Italian Marechiaro

HS Marechiaro

Italian hospital ship Marechiaro was a steam ship originally built by an Italian shipping company, but requisitioned for use as an Italian hospital ship during the First World War...

 sunk on 21 February 1916, was listed as a hospital ship

Hospital ship

A hospital ship is a ship designated for primary function as a floating medical treatment facility or hospital; most are operated by the military forces of various countries, as they are intended to be used in or near war zones....

 and sank with over 200 casualties.
Since Germany was not at war with Italy at this stage, though Austria was, UC 12, like other German U-boats in the Mediterranean, operated under the Austro-Hungarian flag.

Fate

On 16 March 1916 UC-12 was sunk by the detonation of one of her own mines while laying a mine fields off Taranto

Taranto

Taranto is a coastal city in Apulia, Southern Italy. It is the capital of the Province of Taranto and is an important commercial port as well as the main Italian naval base....

 harbour. Italian divers inspected the wreck and established its identity. The knowledge that Germany, technically their ally, was assiduously mining their naval bases was a contributing factor in Italy’s decision in May 1916 to declare war on Germany.
The submarine was raised by Italy and commissioned as X-1 in the Italian Royal Navy

Regia Marina

The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...

.