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The Flush That Sank a Submarine

I've spent half a century writing for radio and print (mostly print). I hope to still be tapping the keys as I take my last breath.

World War II submarines were crude affairs when compared with today’s vessels, but the old ones and new ones share a common problem—how do you dispose of what gets flushed down the toilet?

The waste can’t be flushed directly into the ocean because the external pressure will make it travel the other way. Yuk. Spare a thought for the person who discovered that law of physics. The waste is usually sent into a holding tank and disposed of later.

Origin of the Head

Toilets on ships have been called heads for several hundred years. The word comes from the location of the crapper in the bow or “head” of sailing ships. Ships cannot sail directly into the wind so the bow will always have a breeze coming in from behind or the side to take away any unpleasant odours.

The place where sailors answered a call of nature was above the water line and equipped with slats in the floor. Waves provided a flushing action, but this carried the inherent danger of being washed away with your poop. Timing was everything.

Nowadays, of course, we are all modern and nautical toilets are just like those used by landlubbers.

Sailing ship heads in the prow provided no privacy.

Sailing ship heads in the prow provided no privacy.

New Deep Water Head Developed

Most U-boats of Second World War vintage were equipped with heads that discharged into the sea; a function that only worked at sea level because of that pressure problem.

When submerged, the sailors had to use buckets that could be emptied topside when surfaced. The ventilation systems of U-boats were notoriously awful so . . . But, we don’t need to get too graphic.

By the middle of the war, the Allies had developed tactics that made U-boats at or near the surface sitting ducks; they were being sunk faster than the Germans could replace them.

So, German engineers developed a toilet system that would enable the vessels to stay submerged longer.

U-625 goes to her watery grave in February 1943. She was of the same class as U-1206.

U-625 goes to her watery grave in February 1943. She was of the same class as U-1206.

When the German submarine U-1206 was commissioned in 1944 she was equipped with a new head. It used a fiendish arrangement of high-pressure valves, chambers, and air locks. Finally, a gust of compressed air blew the offensive matter into the ocean.

The problem was that the head was so wretchedly complicated to use that a specially trained operator had to be on hand to supervise the flushing.

Now, there’s a job to be envied and highlighted on your resume.

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U-1206 Runs into Trouble

Under the command of Captain Karl-Adolf Schlitt, U-1206 was sent to do some spying off the east coast of Britain. Some accounts say the orders were to go out into the North Atlantic and wreak havoc among merchant vessels.

According to, “On April 14, 1945, only 8-10 miles off the British coastline, the boat was safely cruising at 200 feet,” when the skipper decided to use the toilet. He also decided to do so without the attendant expert. Poor choice.

A correspondent at picks up the story by saying the captain claimed a break down of the system. A second, more widely reported account, says that Capt. Schlitt “got the order of valves wrong. The result, whether through misadventure or malfunction, was that Schlitt was showered with high-pressure sewage and sea water.”

(Captain Schlitt? What a name to have for this sort of thing to happen to you.)

Seeing their captain emerge from the head decorated in feces would have prompted much ribald humour, but the accident had much more serious consequences.

A submarine head. Definitely read the instruction before use. And, make sure there's a sufficient supply of paper.

A submarine head. Definitely read the instruction before use. And, make sure there's a sufficient supply of paper.

Submarine Forced to Surface

A second design flaw in U-1206 was now exposed. When submerged, the vessel relied on a large battery compartment for power. This was located directly underneath the head.

When seawater and battery acid come together chlorine gas is created and this forced Capt. Schlitt to take his vessel to the surface.

Tony Long, writing for notes that “Unfortunately for the Germans, the boat was only 10 miles off the Scottish coast, and it was quickly spotted by the British.”

Attacked from the air, the submarine was so badly damaged that she could not dive, while four of her crew were killed. Capt. Schlitt ordered the vessel scuttled and abandoned. All the surviving submariners were captured and able to sit out the last few weeks of the conflict in safety.

Capt. Schlitt offered a different and less personally embarrassing version of the catastrophe. According to his official report, the toilet malfunctioned when an engineer was doing maintenance on it.

Bonus Factoids

  • U-1206 was Captain Schlitt’s first and only command. The ill-fated vessel was on its maiden voyage when its toilet malfunctioned.
  • In May 2012, U-1206’s wreck was found in 230 feet of water off the coast of Scotland. Jim Burke, who led the team looking for her told The Scotsman “The feeling on seeing it was one of elation and excitement.”
  • There’s an uncorroborated theory, from the family of a crewman, that Capt. Schlitt deliberately created the lavatory misadventure. In April 1945, the war was almost over and Germany’s defeat was inevitable. Did Capt. Schlitt surrender his ship by making it look like an accident instead of taking his crew out on a pointless and near-suicidal mission? That's a theory.
  • Britain’s wartime leader Winston Churchill said “the only thing that ever frightened me during the war was the U-boat peril.” However, by the summer of 1943, better tactics and weaponry led to increasing numbers of U-boats being destroyed. By the war’s end, three quarters of the German fleet had been sunk and 30,000 of 40,000 submariners had died


  • “April 14, 1945: Tweaky Toilet Costs Skipper His Sub.” Tony Long,, April 14, 2011.
  • “U-1206 Scuttled Due to an Incompetent Flush?” Mike F, World War Militaria, October 9, 2008.
  • “Found After 70 Years, the Wreck of U-1206.” Alistair Munro, The Scotsman, May 29, 2012.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2018 Rupert Taylor


Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on August 31, 2018:

Hi, Rupert, thank you. I enjoy the story.

Rupert Taylor (author) from Waterloo, Ontario, Canada on August 31, 2018:

Thanks Louise. I always learn something in writing them.

Louise Powles from Norfolk, England on August 31, 2018:

I love reading your articles. I always learn something new.

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