Reflecting back on World War II, British Prime Minister Winston Churchill once wrote that “the only thing that really frightened me during the war was the U-boat peril.” U-boats—the German submarine fleet—patrolled the Atlantic throughout the war, wreaking havoc on Allied convoys carrying troops, supplies, and everything else flowing between the United States and Western Europe. Over the course of the war, German forces sank nearly 4,000 ships and took the lives of roughly 75,000 sailors and merchant marines, in no small part due to the advantages gained by this submarine fleet.
Over time, Allied forces developed different ways to detect and, ultimately, destroy these subs. On April 14, 1945, the British managed to sink one of the U-boats without any technological advantages—at least not on the Allies’ part—shortly after it surfaced just off the shores of Scotland.
Why would the U-boat surface there? The crew didn’t have a choice.
Someone flushed the toilet when he shouldn’t have.
That’s not a euphemism for a screwup, either—that’s quite literally what happened. This U-boat was a very new one—it was on its first (and last) patrol—and it had some new features. For example, U-1206 was outfitted with a special type of toilet that allowed the men on board to hit the head while the submarine was well below the ocean’s surface. This wasn’t a simple “do your business and pull the chain” toilet. Operating it—that is, flushing it—required training, and not everyone on the U-boat had been so educated. Those who availed themselves of these toilets during deep-sea dives needed to call in one of these specifically trained toilet flushers to finish the job. Apparently, someone forgot that step.
The errant flush caused a leak and water entered the U-boat’s batteries, which, according to Wired, were located beneath the toilet. The waterlogged batteries began to emit chlorine gas, which is toxic. So the U-boat’s crew, facing near-certain death if they stayed at dive depth, surfaced to air everything out.
Before the crew could fix the problem and clear out the toxic fumes, the ship was detected by the British and, shortly thereafter, sunk by the Royal Air Force. Four men aboard were killed, the other forty-six captured by the British, and U-1206 was destined for an eternity at the bottom of the North Sea, its super-toilets submerged under 200 meters of water.
More than three dozen nations (through 2013) now have submarine fleets. If one were to rank the fleets by the number of subs, Russia, China, and the United States would be in the top four, which makes sense given the respective size of their nations, economies, and militaries. But none of them are atop the list. Number one? Perhaps surprisingly, it is North Korea.