HNLMS O 12

Design and description

The O 12-class submarines were designed to patrol home waters and were the first Dutch boats to have a uniform armament of torpedoes. The boats had a length of overall, a beam of and a draft of. They displaced on the surface and submerged. The submarines had a crew of 31 officers and enlisted men.
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the boats had a range of at and at submerged. The submarines had a diving depth of.
The O 12 class was armed with five 21-inch torpedo tubes. Four of these were in the bow and one in the stern. They were also armed with two Bofors AA guns; these were on single watertight mounts that retracted into the conning tower when submerged.

Construction and career

O 12 was ordered on 4 October 1927 and laid down on 28 October 1928 at the shipyard of Koninklijke Maatschappij De Schelde in Vlissingen. The boat was launched on 8 November 1930 and commissioned on 20 July 1931.
When Germany invaded the Netherlands on 10 May 1940, O 12 was being overhauled at Willemsoord, Den Helder, and had to be scuttled to prevent her capture intact on 14 May. The Germans refloated the submarine and sent her to the Wilton-Fijenoord shipyard in Rotterdam to be repaired. On 30 January 1943, she was taken into service by the Kriegsmarine as UD-2. After serving as a training boat, she was taken out of service on 6 July 1944 and moved to Kiel, where she was scuttled in the harbor in May 1945. Afterwards, UD-2 was raised and demolished.