The German Kriegsmarine possessed two notable midget submarines: the one-man Biber (German for “beaver”) and the two-man Seehund (German for “seal”). Neither U-boat was particularly successful as a weapon against Allied ships and merchantmen.

Influenced by a captured one-man British submarine, a Biber prototype was in place in March 1944, with production models to be in place in the late spring to help thwart the projected Allied invasion of Europe (Operation Overlord). However, the haste with which the pint-sized Biber was developed resulted in funda­mental technical flaws and inadequate operator training. Not until nearly three months after the initial Normandy landings (Operation Overlord) was the first Biber operation launched from a French port northeast of Le Havre. Only two out of 22 Bibers launched reached their operational destination.

A total of 324 Bibers were delivered to the Kriegsmarine. The Biber had a 5-ft periscope, had dual propulsion diesel (surfaced) and electric (submerged) motors, carried two mines, or two torpedoes, or one of each. The Biber had a maximum range of 100 nautical miles at 6.5 knots surfaced.

The Biber midget submarine was truly a sailor’s coffin. In an attack of 18 Bibers on the night of December 22/23, only one returned. Further operations between the 23rd and the 25th achieved no success, and none of the 14 submarines deployed survived. Losses at sea at the end of January, combined with Royal Air Force bombing of launch sites, prevented attacks from being mounted in February 1945. The last Biber mission was a mine-laying operation and took place on the night of April 26, four days short of Hitler’s suicide. Of the four Bibers that took part, one ran aground and three were attacked by P-47 Thunderbolts, which sank two of them.

A far more successful undersea weapon was the two-man Seehund (pl., Seehunde in German) (see photo below). Designed in 1944 and again modeled on a British submarine, the first production contract was let at the end of July. Several Seehund versions were used by the Kriegsmarine during the closing months of the war. Fewer Seehunds entered service (138) owing to labor and raw material shortages and conflicting priorities, but fewer of these midget subs were lost (35). A total of 285 Seehunds were constructed, with a further 93 under construction when the war ended.

The Seehund was 39 ft long, 5-1/2 ft wide, had a submerged speed of 7 knots (under 8 mph), had dual propulsion diesel (surfaced) and electric (submerged) motors, was fitted with a 10‑ft periscope, had a range of 270 or so nautical miles, and was almost impossible to detect by sonar. The midget sub was armed with two torpedoes. From January to April 1945, Seehunds performed 142 sorties, during which they sank eight ships (versus one notable sinking for the Biber) for a total of 17,301 tons and damaged three for a total of 18,384 tons. Seehunds operated mainly off the German coast and in the English Channel. Missions usually lasted five days, though several racked up 10 days. The last Seehund sorties took place just before and after Hitler’s suicide, April 28 and May 2, 1945.

Seehund, a German Midget Submarine, with Torpedo