The Type XXI submarines were a category of German Elektroboot (electric boat) submarines, powered by diesel-electric engines, designed during World War II.

A total of 118 were constructed, but only four of them were fully prepared for combat operations.

Despite this, during the war, only two of these submarines were actually put into active service and conducted patrol missions, although they were not engaged in combat.

They typically measured 76.70 meters (251 feet 8 inches) in length, 8 meters (26 feet 3 inches) in width, and had a draft of 6.32 meters (20 feet 9 inches). However, the Type XXIC was longer, spanning 83 meters (263 feet).

The Wilhelm Bauer was equipped with a total of six torpedo tubes at its bow and four 20mm anti-aircraft guns. In contrast, the Type XXI submarine had the capacity to carry up to twenty-three torpedoes or, alternatively, seventeen torpedoes and twelve sea mines. This represented a significant enhancement compared to the Type VII C, which had a maximum capacity of fourteen torpedoes.

The Type XXI U-Boats were powered by two MAN SE supercharged six-cylinder M6V40/46KBB diesel engines, each generating 4,000 metric horsepower.

Along with two Siemens-Schuckert GU365/30 double-acting electric motors providing 5,000 PS each and two Siemens-Schuckert silent running GV232/28 electric motors with 226 PS each.

Groundbreaking

These submarines represented a groundbreaking shift from earlier designs, as they were specifically designed for extended submerged operations rather than primarily functioning as surface vessels with limited submergence capabilities to evade detection.

They incorporated numerous batteries to significantly extend their submerged endurance, enabling them to remain submerged for several days at a stretch. Recharging was only required by surfacing to periscope depth and using a snorkel.

The Type XXI submarines introduced several notable improvements, such as enhanced underwater speed due to improved hull design, substantially reduced diving times, power-assisted torpedo reloading, and improved living conditions for the crew.

Nevertheless, the design also exhibited significant flaws, including mechanical unreliability and susceptibility to combat damage.

Furthermore, the production of Type XXI submarines was rushed, commencing before the completion of the design phase.

The inexperienced facilities tasked with constructing these vessels struggled to meet the necessary quality standards, further complicating their operation and maintenance.

Had a Vast Range

These submarines had a maximum surface speed of 15.6 knots and a submerged speed of 17.2 knots. In silent mode, they could operate at a reduced speed of 6.1 knots when submerged.

When underwater, they could cover 5 knots for 340 nautical miles, and when surfaced, they could travel an impressive 15,500 nautical miles at 10 knots.

In 1945, ‘Wilhelm Bauer‘ U-2540″ was intentionally scuttled by its own crew as part of the “Aktion Regenbogen.” After resting on the seabed of the Flensburg Fjord for a period of 12 years, the submarine was raised from the depths in 1957 and subsequently placed into service with the German Navy, bearing the new name “U-Wilhelm Bauer,” three years later.

Armament-wise, the Type XXI U-Boats were equipped with six 53.3 cm torpedo tubes in the bow and four 2 cm C/30 Flak 30 anti-aircraft guns.

They had the capacity to carry either twenty-three torpedoes or seventeen torpedoes and twelve mines. The submarine’s crew consisted of five officers and fifty-two enlisted men.

Attack Strategy

There were three variants of the Type XXI – the Base XXI (also known as XXIA), the XXIB, and the XXIC, with the primary difference being in their armament, except for the XXIC, which was longer than the other variants. Three additional variants (XXID, XXIE, and XXIF) were proposed but never constructed.

Complete sections (pressure hull with outer skin) of submarine type XXI. Section 8th in the background and probably 7th in the front.

In terms of attack strategy, the Type XXI submarines employed a unique approach. When a target was sighted, they would accelerate at full speed on a direct collision course with the target, regardless of its type, while maintaining attack depth.

Without using the periscope, the distance and bearing of the target could be accurately calculated by a fire control center within the submarine.

After completing the attack run, the Type XXI would swiftly escape at flank speed at depth, taking advantage of the fact that most allied sonar systems were unable to detect the boat’s high speed of 13 knots.

Type XXI submarines are regarded as the pioneering “true” submarines due to their capability to carry out wartime operations while maintaining a nearly constant state of submersion.

Despite their exceptional qualities, these submarines had their flaws. Nevertheless, many historians consider them the best submarines of World War II, and they served as a model for numerous post-war submarines, especially those of the Soviet Union.

‘Wilhelm Bauer’ U-2540 Scuttled

As for U-2540, it was laid down on October 28, 1944, and commissioned in February 1945. It served in the German Kriegsmarine for just under three months as a training vessel, as fuel shortages prevented it from going on patrols.

Instead, U-2540 was towed to Swinemünde and scuttled near the Flensburg lightship on May 4, 1945, along with several other ships to prevent capture by the advancing Red Army.

At the end of the war several Type XXI were in construction at Bremen. They were shared among the allies (USSR, U.S., Britain, France).

U-2540 remained underwater for 12 years until it was salvaged in 1957 by the Bundesmarine (West German Navy).

After refurbishment, it was repurposed as a research vessel and renamed Wilhelm Bauer in honor of Germany’s first U-boat designer and the builder of the first German submarine, the Brandtaucher of 1850 (now a museum ship).

Wilhelm Bauer, designated as Class 241, served as a test boat from 1960 to 1968 and was decommissioned for the first time. In 1970, it was recommissioned as a training submarine and a technology test vessel, operated by a civilian crew.

It played a pivotal role in testing the technical innovations of the 206 U-boat class. However, in 1980, Wilhelm Bauer was involved in an underwater collision with the German destroyer Zerstörer 3 (D172) (formerly USS Wadsworth (DD-516) of the Fletcher class).

As a result, it was retired from service on May 6, 1980, at Eckernförde, and ultimately decommissioned for the last time on March 15, 1982.

‘Wilhelm Bauer’ U-2540 Up For Sale

The German Ministry of Defence put Wilhelm Bauer (formerly U-2540) up for sale, and it was later acquired by the board of trustees of the German Maritime Museum Association and the Deutsches Schiffahrtsmuseum (German Maritime Museum) in Bremerhaven.

The design of the Type XXI had a direct impact on the development of advanced post-war submarines.

The submarine was painstakingly restored to its original World War II configuration, including the installation of mock 2cm Flak 30 AA Guns and the removal of its glazed bridge from the Bundesmarine. Its propellers were also placed at the museum’s entrance.

The Wilhelm Bauer, now bearing the name U-2540 again, was opened to the public as a museum ship on April 27, 1984, in Bremerhaven.

It is currently sponsored by the Wilhelm Bauer Technology Museum Association and is the last Type XXI U-boat afloat and the last unmodified U-boat accessible to the public.

It is one of only four WWII U-boats left on display, alongside U-505, U-534 (Type IX and IXC/41, respectively), and U-995 (Type VIIC/4).