The submarine's hull groaned at 180 meters—far deeper than it was ever meant to go—as chlorine gas seeped through the darkness.

The Sinking of U-473: When Depth Charges Found Their Mark

A German submarine crew's final hours in the Bay of Biscay

A crippled German U-boat surfaced to fight rather than drown, staging a seven-minute gun battle before sinking.

The Atlantic swells rolled gray and indifferent on the morning of May 5, 1944, as Oberleutnant zur See Heinz Sternberg ordered U-473 to surface for air. His crew of forty-eight men had been submerged for hours, their oxygen growing stale, their nerves frayed by the constant threat of Allied aircraft that now owned the skies above the Bay of Biscay.

What Sternberg didn't know was that RAF Coastal Command had been tracking his boat since dawn. A Sunderland flying boat from No. 461 Squadron RAAF—crewed by Australians far from home—had picked up the submarine's signature and was circling, waiting.

The moment U-473's conning tower broke the surface, hell descended. Flight Lieutenant R.D. Lucas pushed his Sunderland into a diving attack, releasing depth charges that straddled the submarine's hull. The explosions lifted the U-boat partially out of the water, rupturing seams and flooding compartments. Sternberg ordered an emergency dive, but the damage was catastrophic.

For the next three hours, U-473 became a steel coffin slowly filling with seawater. Chlorine gas from ruptured batteries began poisoning the air. Men worked frantically at hand pumps while others sealed compartments wher…

💡 The Sunderland flying boat that attacked U-473 was crewed entirely by Australians serving with the RAF—fighting a German submarine in French waters while 15,000 kilometers from home.