German submarine U-1206

German submarine U-1206 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. She was laid down on 12 June 1943 at F. Schichau GmbH in Danzig and went into service on 16 March 1944. The submarine was scuttled on 14 April 1945 after being attacked by British forces after she was forced to the surface by problems arising from a malfunctioning plumbing system.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-1206 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-1206 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, (220 rounds), one 3.7 cm Flak M42 and two twin 2 cm C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.

Service history
After being commissioned, under the command of Oberleutnant zur See 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 27 year old Kapitänleutnant Karl-Adolf Schlitt. The boat was then fitted with a Schnorchel underwater-breathing apparatus before being released for patrol duties.

The boat's emblem was a white stork on a black shield with green beak and legs.

Patrols
On 28 March 1945 the submarine departed from Kiel for its first training patrol in the North Sea, returning on 30 March. The submarine departed from Horten Naval Base for a one-day patrol on 2 April, and its first active patrol began on 6 April when it departed from Kristiansand.

Fate
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 an extremely complicated procedure and special technicians were trained to operate them. Incorrectly opening valves in the wrong sequence could result in waste or seawater flowing back into the hull.

On 14 April 1945, 24 days before the end of World War II in Europe, while U-1206 was cruising at a depth of 200 ft, 8 nmi off Peterhead, Scotland, misuse of the new toilet caused large amounts of seawater 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 head) causing them to generate 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 had died of illness a day before the mishap, three men drowned in the heavy seas after abandoning the vessel and 46 were captured.

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 underwater. The site survey performed by RCAHMS suggests that the leak that forced U-1206 to surface may have occurred after running into a pre-existing wreck located at the same site.

A large number of sources incorrectly attribute this incident to GS U-120 (1940).Sources asserting incorrectly that U-120 sank because of a malfunctioning toilet include: Sources reporting U-1206 sank because of a malfunctioning toilet include: