While the Type XXI subs sank no ships, their potential terrified Allied navies, prompting intensified anti-submarine efforts.
Although they lost World War II, the Nazis were more technologically advanced than their Allied rivals in multiple ways. Berlin’s problem was scale—and trying to do too much with too few resources.
One area that the Germans were highly advanced in was undersea warfare. The German Type XXI submarine, often referred to as the Elektroboot or “electric boat,” represents one of the most advanced naval innovations of the war. Developed by Nazi Germany’s Kriegsmarine in response to mounting Allied anti-submarine warfare (ASW) successes, this diesel-electric submarine was designed to operate primarily underwater, marking a significant shift from earlier U-boat models.
As the Battle of the Atlantic intensified, traditional submarines like the Type VII and Type IX became increasingly vulnerable to radar and sonar detection. The Type XXI aimed to restore Germany’s underwater dominance—but its late introduction limited its impact on the war’s outcome.
The Type XXI Submarine’s Specifications
- Year Introduced: 1944
- Number Built: 118
- Length: 251 ft (76 m)
- Beam (Width): 26 ft 3 in (8 m)
- Displacement: 1,621 tons submerged
- Engines: Two MAN diesel engines, adapted for underwater use
- Top Speed: 15.6 knots (18 mph, 28.9 km/h) surfaced; 17.2 knots (19.8 mph, 31.8 km/h) submerged
- Range: 17,800 mi (28,700 km) surfaced
- Armaments: Six 21-inch torpedo tubes; four 20mm anti-aircraft guns (surface use only)
- Crew: 57
About the Type XXI Submarine
Beginning in 1943 under the direction of engineers like Hellmuth Walter, the Type XXI was in a league of its own. Unlike previous German U-Boats, which were essentially surface vessels that could submerge briefly, the Type XXI was engineered as a long-term submersible. Key innovations included a streamlined hull for reduced drag, a snorkel device allowing its diesel engines to run while submerged, and massively increased battery capacity—three times that of its predecessor, the Type VII—for extended underwater endurance.
The “electric boat” featured hydraulic torpedo reloading systems, enabling rapid firing without surfacing. It also incorporated advanced sonar and radar-absorbing coatings to evade detection. This design also prioritized speed and stealth, allowing the Type XXI to outmaneuver Allied convoys and escorts.
Although the Type XXI was a relatively early sub, its production was quite advanced for its era, reflecting the supremacy of German technological development. Unlike most submarines of the war, it had a modular design; sections were built in factories, then assembled at shipyards to accelerate output amid bombing raids.
Over 118 units were completed by war’s end, but quality issues from rushed construction plagued many of the submarines, limiting their effectiveness.
Despite its promise, the Type XXI entered service too late to alter WWII’s naval balance. The submarine’s first operational patrol occurred in April 1945, with U-2511 under Commander Adalbert Schnee encountering a British cruiser but aborting attack due to the war’s imminent end. Only a handful of Type XXIs saw combat; most were still in training or en route when Germany surrendered in May 1945.
Allied bombing disrupted production, and faulty batteries along with untrained crews were among some of the late-stage war issues that afflicted the Type XXI. One notable incident involved U-3008, which evaded Allied forces but achieved no sinkings. After Germany’s surrender, several of the subs were scuttled or captured, with U-2540 (later known as the Wilhelm Bauer) surviving as a museum piece.
While the Type XXI subs sank no ships, their potential terrified Allied navies, prompting intensified anti-submarine efforts. Had they been deployed more aggressively in 1944, when they first entered service, they might have prolonged the Battle of the Atlantic.
The Type XXI Went on to Influence Cold War Submarines
Type XXI’s influence extended far beyond World War II, though. Captured examples, like those studied by the Allies, shaped Cold War submarine designs. The Soviet Union’s Whiskey-class and the US Navy’s Tang-class borrowed its streamlined hull and battery tech. Modern nuclear submarines echo its emphasis on submerged performance.
The German Type XXI stands as a testament to Nazi Germany’s desperate ingenuity in WWII. Though it arrived too late to turn the tide, its breakthroughs in underwater warfare redefined submarine technology. Indeed, the sub’s enduring legacy, ironically, is how it influenced the subsequent submarine designs of the two powers that defeated Germany.
About the Author: Brandon J. Weichert
Brandon J. Weichert is a senior national security editor at The National Interest. Recently, Weichert became the host of The National Security Hour on America Outloud News and iHeartRadio, where he discusses national security policy every Wednesday at 8pm Eastern. He is also a contributor at Popular Mechanics and has consulted regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including The Washington Times, National Review, The American Spectator, MSN, The Asia Times, and others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Shutterstock / Maurizio Fabbroni.
