Its skipper, twenty-five-year-old Lt. James S. Launders who in addition to sinking twelve Axis surface ships, had dispatched the surfaced submarine U-711 in November 1944.

A very interesting story from World War II. What Happened The One (and Only) Time Submarines Battled?by Sebastien Roblin.

At first the I wrestled with the headline. I can think off the top of my head multiple instances where one submarine sank another in WWII. Only then did I realize Roblin was making the distinction of two enemy submarines engaging with one another with both simultaneously underwater. Fair enough. That was pretty rare, though I have a hazy recollection of a Japanese submarine sinking an American submarine, both underwater, towards the close of the war, when American subs were operating in the perilously shallow waters around Japan. But perhaps I am misrembering.

But Roblin story is an interesting one. A teaser:

Despite this formidable advantage, Wolfram’s mission proved ill-omened from the start. U-864 initially set off from Kiel on December 5, 1944, but ran aground while transiting through the Kiel canal. Wolfram decided to have the ship undergo repairs in Bergen, Norway. But in Bergen, its armored pen was hit with twelve-thousand-pound Tall Boy bombs dropped by British Lancaster bombers on January 12, 1945, causing even more damage.

Unfortunately for Wolfram, the United Kingdom had long ago cracked the Enigma code, which German U-Boats used to communicate with the Naval headquarters. By February, the British Navy had decoded messages relating U-864’s mission, and decided to set a trap.

HMS Venturer, the first of the new V-class submarines, received orders from the Royal Navy Submarine Command to hunt down and destroy U-864 off the island of Fedje, Norway. The smaller, shorter-range British submarine carried only eight torpedoes to U-864’s twenty-two, but it was nearly 50 percent faster underwater, at ten miles per hour.

Venturer arrived at its station on February 6. Its skipper, twenty-five-year-old Lt. James S. Launders, was a decorated submarine commander, who in addition to sinking twelve Axis surface ships, had dispatched the surfaced submarine U-711 in November 1944.

Well worth a read.