German submarine U-1206

German submarine U-1206 was a  German Type VIIC U-boat of the Kriegsmarine during World War II. She was laid down on June 12, 1943 at F. Schichau GmbH in Danzig and went into service on March 16, 1944. The boat's emblem was a white stork on a black shield with green beak and legs.

Service history
After being commissioned, under the command of Oblt. Günther Fritze, the submarine took part in training exercises with the 8th U-boat Flotilla until July 1944 when it was assigned to the 11th U-boat Flotilla. Command was handed over to Kptlt. Karl-Adolf Schlitt. The boat was then fitted with a Schnorchel underwater-breathing apparatus before being released for patrol duties.

Patrols
On March 28, 1945 the submarine departed from Kiel for its first training patrol in the North Sea, returning on March 30. The submarine departed from Horten for a one-day patrol on April 2, and its first active patrol began on April 6, when it departed from Kristiansand. On April 14, while on patrol, the vessel sank after the toilet was operated improperly.

Sinking
U-1206 was one of the late war boats fitted with new deepwater high-pressure toilets which allowed them to be used while running at depth. Flushing these facilities was extremely complicated and special technicians were trained to operate them.

On April 14, 1945, 8 mi off Peterhead, Scotland, while cruising at a depth of 200 ft, misuse of the new toilet caused large amounts of water to flood the boat. According to the Commander's official report, while in the engine room helping to repair one of the diesel engines, he was informed that a malfunction involving the toilet caused a leak in the forward section. The leak flooded the submarine's batteries (located beneath the toilet) causing them to release chlorine gas, leaving him with no alternative but to surface. Once surfaced, U-1206 was discovered and bombed by British patrols, forcing Schlitt to scuttle the submarine. One man died in the attack, three men drowned in the heavy seas after abandoning the vessel and 46 were captured. Schlitt recorded the location as 57.4°N, -1.61667°W but the wreck could not be relocated.

During survey work for the BP Forties Field oil pipeline to Cruden Bay in the mid 1970s, the remains of U-1206 were found at 57.35°N, -1.65°W in approximately 70 m of water. The site survey performed by RCAHMS suggests that the leak that forced U-1206 to surface may have occurred after running into a wreck located at the same site.

A large number of sources attribute this incident to GS U-120 (1940).