Type XXI U-boats, also known as the "Elektroboote", were the first submarines designed to operate entirely submerged, rather than as surface ships that could submerge as a temporary means to escape detection or launch an attack.

Type XXIs had much better facilities than previous classes, with a freezer for foodstuffs and minor conveniences for the crew such as a shower and wash basin. They were much quieter, and enjoyed a hydraulic torpedo reload system that allowed all of its six torpedo tubes (all six were located at the front) to be reloaded faster than a Type VIIC could reload a single tube. In fact, the Type XXI could fire 18 torpedoes in under 20 minutes. The torpedo carrying capacity was 23 torpedoes, or 17 torpedoes and 12 sea mines. Improvements in battery design yielded a storage capacity roughly three times that of a Type VIIC, giving these boats enormous underwater range. They could travel submerged at about five knots (9 km/h) for two or three days before recharging the batteries, which took less than five hours on the snorkel.

Because of their hull design these ships could actually travel faster underwater than on the surface, albeit only for a limited amount of time. This, combined with longer dive times at reduced speeds, made them much harder to chase and destroy. It also gave the boat commander a 'sprint ability' when positioning the boat for an attack. Older boats had to surface in order to sprint into position. This often gave the boat away, especially after aircraft became available for convoy escort.

Between 1943 and 1945, 118 boats of this type were built by Blohm + Voss of Hamburg, AG Weser of Bremen, and F. Schichau of Danzig. The boats were built at an increased speed, as compared to the older types. This was due to the fact that the whole hull was constructed from 8 pre-prepared sections which were to be assembled into a ready boat, after being transported from the various scattered factories they were made in. However, despite such number of boats built, only one, U 2511, had begun a combat patrol by the end of World War II. This was in part a result of the lenghtened training process, as the crews had to be trained to operate the new, sophisticated technology. Most boats were scrapped or scuttled after the war, but eight were taken by the Allies for evaluation and trials. The United States received U 2513 and U 3008, which were commissioned into the United States Navy. U 3017 was commissioned into the Royal Navy as HMS N41, and U 2518 became French submarine Roland Morillot. U 3515, U 2529, U 3035, and U 3041 were commissioned into the Soviet Navy as B 27, B 28, B 29, and B 30 respectively. Those boats influenced new Soviet submarine classes known by the NATO reporting names Zulu and Whiskey, although they were not copies of a Type XXI, Whiskey class being smaller and less sophisticated.

A ninth XXI also saw service after the war: U 2540, which had been scuttled at the end of the war, was raised in 1957 to become the research vessel Wilhelm Bauer of the Bundesmarine and the only XXI remaining.

Specifications

• Displacement: 1621 t/1819 t, 2100 t full load
• Length: 76.7 m oa, pressure hull 60.5 m
• Beam: 5.3 m pressure hull, 8 m oa
• Draft: 6.3 m
• Height: 11.3 m
• Propulsion: 4000 hp (3 MW) surfaced = 15.6 kt (29 km/h), 4400 hp (3.3 MW) submerged = 17.2 kt (32 km/h)
• Range: 25,000 km (15,500 miles) at 10 kt (19 km/h) surfaced, 550 km (340 miles) at 5 kt (9 km/h) submerged
• Crew: 57

See also

• List of Type XXI Submarines
• Romeo class submarine: The Soviet Project 633 submarine class derives from the Type XXI boats.

Submarine classes | World War II submarines of Germany | Type XXI U-boats

U-Boot-Klasse XXI | U-Boat Tipo XXI | Okręty podwodne typu XXI