The Submarine That Sank Because Someone Flushed The Toilet Wrong

It only managed one patrol before flushing away its potential

(By David W. Taylor Model Basin, U.S. Navy — This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: white background. The original can be viewed here: Type VIIC U-boat schematic drawing.jpg: . Modifications made by TilmannR., Public Domain, https://commons.wikimedia.org/w/index.php?curid=76292949)

The German submarine, U-boat U-1206, was launched on December 30th, 1943. It was a so-called late-war boat that was outfitted with the latest technology. One such technology was a specialized toilet system that allowed sailors to flush their waste directly out into the ocean rather than storing it in special chambers within the submarine itself. This new system was known as a deepwater high-pressure toilet, and it had a number of benefits over the old chamber system.

A toilet that could jettison waste directly into the ocean was much quieter than an onboard septic tank. Septic tanks added to the weight of the submarine and required frequent dumping. Blowing the contents of a shipboard waste tank was noisy, and it would immediately attract the attention of any nearby destroyers or submarines. The alternative was to return to port whenever the sub accrued enough poop, which could be disruptive to a long-term mission or task. By contrast, being able to shoot feces directly into the ocean with one flush would be quiet and would allow the submarine to remain submerged and at sea for far longer. These benefits seemed to outweigh the drawbacks as Germany began installing these new toilets on all of their new submarines during the last year of the war. The trouble was that this new deepwater high-pressure toilet was incredibly complicated.

For anyone who has never been on a submerged submarine or in space, it can be hard to wrap your head around the fact that flushing a toilet can be difficult. You just push the handle, and the waste vanishes and is replaced with clean water. When you are hundreds of feet underwater, that process is a lot more complicated. These deepwater toilets were so complicated that there were a number of specialized technicians who were trained in the art of flushing these toilets. Regular sailors were forbidden to attempt to flush on their own and had to wait for a technician to come and help them.

The toilets require a number of valves and pressure switches to be activated in a specific order. This is required to equalize the pressure between the toilet plumbing and the water outside of the boat. Do it wrong, and you can…