U-12 was a type U-9 U-boat ordered on the 15th July 1908 from the Kaiserliche Werft Yard, at Danzig. Built as yard number 7 she was launched on 6th May 1910 and, after fitting out, commissioned on the 13th August 1911. There were four U-boats built in her class which displacement of 611 tons submerged. They were 57.4m long, 6m wide 7m high to the top of the conning tower. The submarines were powered by two kerosene engines for surface use and two electric motors for underwater use giving them a top speed of 14 knots on the surface or 8 knots submerged. The type U-9 U-boats had 2 bow and 2 stern torpedo tubes but only carried 6 torpedoes. Normally the class also carried a 105mm deck gun, but for some reason this wasn't fitted to U-12.
On 11th November, 1914, under command of Walter Forstmann, she sank the British minesweeper HMS Niger off Deal and in January 1915 she was involved in Germany's experiment with submarine aircraft carriers and in January 1915 she became the first of this type when she left Zeebrugge carrying a Friedrichschafen FF29 seaplane lashed onto her deck. The heavy swell soon forced U-12 to launch the aircraft which went on to fly along the English coastline and return to Zeebrugge.
In March 1915 with a crew of 29 under the command of Hans Kratzsch and operating as part of the II Flotilla, U-12 was patrolling off the east coast of Scotland. On 9th March she torpedoed and sank the British steamship Aberdon off St Abbs Head but her success was short lived as the following day she was spotted by the trawler Duster and trawlers of the Auxiliary Patrol, and the 1st Destroyer Flotilla was dispatched to intercept her. At 10:10 on the 10th March HMS Attack spotted her and opened fire. 2 minutes later HMS Ariel also saw her starting to dive and turned towards the periscope, ramming her on the port side. Badly damaged the U-12 surfaced and immediately came under fire from the destroyers, now joined by HMS Acheron, and her crew tried to escape. Kratzsch had been killed in the gunfire and, with a conning tower hatch only able to be opened half way, only 2 officers and 8 crew managed to make it out before she sank rapidly, taking the rest of her crew with her.
The Wreck Today
The U-12 is a war grave and this should be respected by divers visiting the site. Today she sits upright, largely intact and proud of the seabed in around 48 metres in position 56°14.617'N, 001°51.421'W (WGS84). The wreck sits around 3-4 metres above seabed level at most, although a net attached to her bow stands slightly higher. Note there are a number of fishing nets draped across her, the two key sections are on the bow and the stern and propellors, so take care when close to these hazards. Having dived this wreck on a number of occasions, visibility is generally good and the nets are easily seen.
U12 Dive slideshow
In good visibility the wreck is spectacular. The pressure hull is coated in colourful sealife and there is plenty to see and explore. Probably the most interesting and photogenic areas are the stern and the central conning tower where the diver can see down through the hatch, I found myself reflecting on the last minutes of the crew in such tight and cramped conditions.