One of the most spectacular, albeit minor, Allied victories of World War II had absolutely no Allied involvement whatsoever.

It came in the form of the Nazi submarine U-1206. The Type VIIC boat was a technological marvel armed with two anti-aircraft guns, five torpedo tubes, and most impressively, a complex toilet that could flush waste into the ocean from deep below the surface.

So complex was the sub’s plumbing apparatus that each crewman of the U-1206 needed to be specially potty trained on its operational capabilities prior to its April 1945 launch from Kristiansand, Norway — a matter of weeks before the war in Europe ended.

The boat was just eight days into its maiden patrol when its captain, 27-year-old Karl-Adolf Schlitt, heard nature’s call to expel the sort of bodily ordnance that rhymed with his name.

The captain’s constitutional relief, however, soon turned to psychological stress when the complicated flushing mechanism proved too difficult for the young officer to operate.

Schiltt summoned an engineer for help, but when the crewman confidently turned an incorrect valve, a mixture of sewage and seawater burst through the compartment and spread to other parts of the submarine.

Large batteries that were housed beneath the bathrooms were soon underwater, the mixture of sewage, seawater and battery acid creating a deadly chlorine cocktail that threatened to suffocate the crew.

Schlitt recalled the incident in a report contained in the German U-boat archive.

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“I was in the engine room, when, at the front of the boat, there was a water leak,” he said, deflecting any and all fecal responsibility.

But as the ancient Bavarian saying goes, “He who denied it, supplied it," and most accounts place the young captain in the head during the accident.

If toxic gas and horrendous sewage spreading throughout the boat weren’t bad enough, the sub’s bilge pumps then malfunctioned. The captain had no choice but to order the submarine to surface.

The fortunes of U-1206 only got worse from there.

As soon as the boat appeared above the waves off the northeastern coast of Scotland, it was spotted by Allied aircraft.

Schlitt responded by destroying the boat’s classified equipment — after destroying its bathroom — and ordering his men into lifeboats. He then scuttled the submarine, sending it to the bottom of the North Sea, where it remained undiscovered until an expeditionary team located it nearly 70 years after Schlitt’s legendary stool.

Four men died in the ordeal.

In the end, the U-boat became the quintessential example for every grandfather who has ever railed against new technologies because “they just add to the list of things that can go wrong!”

Loose lips might sink ships, but expelling bloat can damn a boat.