were preceded by the shorter Type VIIB submarines. U-1206 had a displacement of when at the surface and while submerged. She had a total length of, a pressure hull length of, a beam of, a height of, and a draught of. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder superchargeddiesel engines producing a total of for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to. The submarine had a maximum surface speed of and a maximum submerged speed of. When submerged, the boat could operate for at ; when surfaced, she could travel at. U-1206 was fitted with five torpedo tubes, fourteen torpedoes, one SK C/35 naval gun,, one Flak M42 and two twin 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.
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, 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 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 died in the attack, three men drowned in the heavy seas after abandoning the vessel and 46 were captured. During survey work for the BPForties Fieldoil pipeline to Cruden Bay in the mid 1970s, the remains of U-1206 were found at in approximately 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 pre-existing wreck located at the same site. A large number of sources incorrectly attribute this incident to. Many sources incorrectly report that U-120 sank due to a malfunctioning toilet.
