The U-1206 was commissioned on March 16, 1944 and a type 7C U-boat. This type U-Boat was equipped with a new type of toilet designed to allow the submarine to dive deeper and avoid Allied attack. It was a very complicated high pressure valve system which required special training to use them.
After Captain Karl-Adolf Schlitt and the crew received its assignment and they trained with the u-boat for the rest of 1944. In early 1945 they were sent on training patrols in the North Sea after which they were finally ready for the real thing.
Their first and only patrol started on April 6th 1945 and lasted only 8 days, they left from Kristiansand, Norway heading towards the British Islands in search of Allied shipping. All went well until on April 14th 1945 a crew members, reportedly the captain, used the head (toilet) and had trouble operating it. An Engineer was called to help and he opened the wrong valve.
This caused water to enter the submarine which flooded forward compartments and then the batteries. That in turn caused highly poisonous chlorine gas to form in the u-boat leaving Captain Schlitt with no other option than to surface the ship.
Unfortunately for the Germans, they were very close the the Scottish coast and quickly spotted. The crew was frantically blowing clean air into their U-Boat when they were spotted by Allied aircraft. Being unable to enter the U-Boat and dive because of the Chlorine gas the Captain Schlitt decided to let the U-Boat sink. This ended his first and only combat command.
Three crew members drowned when the u-boat went down, 37 crew members were rescued and entered captivity. Soon to be followed by their colleagues as by then World War 2 was nearly over.
The wreck lay undiscovered until the 1970s when it was rediscovered when a pipeline was build.