Type XXI U-Boat

The History of Type XXI Submarines

The XXI series submarines, developed by the German Navy during World War II (1939-1945), were revolutionary on many levels and are seen by the service as their war-winning design - to regain control of vital Atlantic Theater. This submarine was the first to operate faster underwater than on it, and it opened a new chapter in submarine warfare and constructiontracing the roots of submarine work back to the Cold War (1947-1991).

Planning

The

Model XXI is designed for long submerged operations with a focus on a powerful motor with a density battery built directly into the hull. This allowed these boats to generate more power underwater than ships on the surface - a distinct advantage over the diesel-electric powered boats of the time, with their closed-circuit turbine engines.

The Type XXI series is also known as the "Elektroboot" ("Electronic Boat") due to its heavy reliance on electrical engineering in its design.

German Admiral Karl Donitz with his crew planning the advanced Type XXI that will be the new working backbone of the German U-boat fleet - this was before the design challenge. Germany has been at war since September 1939, and in November 1942 Donitz met engineers in Paris, France to lay the foundation for a new class of submarines to develop a new, more powerful attack submarine that would Replacing IIC class submarine ships in terms of capability and performance.

In this context, Dr.'s design work was directed by Walter Hellmuth, but his submarine was so advanced that it was impractical to design, develop and build in wartime, so it was decided to apply his hull work to a transitional vessel design , the design will be put into service immediately and in the hands of German U-boaters in a very short time.

Basic attributes

The original teardrop-shaped hull was combined with a conventional hybrid (diesel-electric) propulsion system, which was incorporated into the overall streamlined shape. Internally, the pressurized fuselage adopts a figure-8 cross-section, with the upstream span being larger than the downstream span. Externally, the dive plane is retractable and only comes into play when needed. The powerplant was placed in the stern, and the torpedo room was in the bow. The central section will be reserved for the command center and crew area.

On board will be up to 57 crew members and facilities such as upgraded berths, showers, integrated air recovery and air conditioning systems, and frozen food storage facilities.

Set sail!

One of the biggest changes to the design of the German U-boats of the Type XXI was the streamlined shape of the sails - many of the protrusions and platforms common on U-boats at the time were gone, replaced by a low profile build above the midship. All the usual protrusions (periscopes, snorkels, antennas) are located on top of the sails, the snorkel is especially noteworthy because it uses a double tube shape with a valve to raise the sight to the waterline when the boat is fully raised Above submersion - which in turn allows the ship to maintain its stealth advantage, while still emitting dangerous CO2 gas due to being close to (not) the surface of the water.

The valves also prevent sea water from entering the area, but the danger remains that the valves are closed and overlooked - because if left unchecked, the diesel engine will continue to run, and the crew who might be sucking in the air inside the U - Boots will kill.

Type XXI is not the usual deck gun, but a pair of anti-aircraft (AA) turrets (2 x 20 mm) mounted on the front and rear fairings of the conning tower. Both are operated remotely from the ship, eliminating the need for rifle crews to be exposed to the elements to defend against aerial attackers (the biggest threat to WWII submarines).

Therefore, no conventional deck guns were installed, although the turret was originally intended to carry a 30mm gun for ground operations.

Special Systems

The boat is fitted with an emergency steering mechanism at the stern as insurance should the main wheelhouse be damaged in any way. The installed radar consists of two working parts (and its sub-parts): a FuMB Ant 3 Ball radar detector (coupled to the antenna mount) and a FuMO 65 Hohentwiel U1 radar with an F432 D2 series transmitter.

The passive component of the sonar system is the passive sonar group listening device (GHG) mounted on the keel. The active part becomes the advanced line-of-sight "Underwater Locator Nibelon".

Armed

On the bow, the torpedo room has been edited with the sonar so it should receive target data from the sonar room and feed the data into the new attitude independent torpedo. A semi-automatic hydraulic system was designed to assist the crew in reloading torpedoes, providing a reload time of just 20 minutes to fire three salvos of six torpedoes each. Older submarines took about ten minutes to load one torpedo (!).

Therefore, the probability of the ship being killed was quite high at the time, as few (if any) ships were able to respond in time to such an attack. The ship is equipped with 6 x 533mm torpedo tubes, all forward, and has undergone up to 23 reloads, although this total can be reduced to make room for TMC mines.

The ship did not have rear-mounted torpedo tubes, which was common in submarines of the time.

Shipbuilding

From the looks of it, the Type XXI's design is turning into a very stealthy underwater monster. Its powerplant consists of two MAN M6V40/46KBB 6-cylinder supercharged diesel engines rated at 3,900 hp for ground operation and two SSW GU365/30 double-acting electric ("crawl") engines rated at 4,900 hp. The boat relies on 2 x SSW GV232/28 motors for silent operation, but can only handle 5.5 knots in this mode. The battery pack consists of a 62 cell 2 x 21 MAL 740 series. The collective propulsion scheme makes the Type XXI faster underwater than on the surface, reaching 17.2 and 15.7 knots, respectively.

Range is also remarkable, these boats can reach 15,500 nautical miles (at a constant speed of 10 knots).

Like any diesel-electric boat, the Model XXI still had to recharge its batteries by surfacing (and emit dangerous CO2 gas), making any boat of that era very vulnerable to enemy attack. However, the clever snorkel design mitigates this somewhat, as it keeps the boat underwater and allows the battery to recharge in four hours every few days.

Size

At the time of construction, the base ship had a displacement of 1,620 tons and a submerged displacement of 1,820 tons. Dimensions include a length of 251.7 feet, a beam of 26.2 feet and a draft of 20.8 feet.

The future of submarines

The Model XXI is revolutionary in many ways in its design - it runs quieter in water than anything else, reaches deeper depths, and travels farther than anything else. In addition, the performance is excellent and the firepower is satisfactory. Its importance to the German cause in mid-1943 led to an immediate shift in construction from the current Type VII to the untested Type XXI.

No new Type XXI prototypes were ordered to justify certain design components, and it went back to following the plan until the end of the war.

Assembly

Another revolutionary feature of the Type XXI was its construction process - the eight separate sections that make up the fuselage were constructed prior to final assembly. This aids production, but makes delivery and ensuring certain tolerances are met more difficult (accuracy is key to hull construction for obvious reasons). Such a manufacturing process involves more than 30 German companies and requires a total of 11 meters to connect the fuselage sections. The German Navy delayed the contract for the 118 ships from 1943 to 1945, with an original delivery date of April 1944 - but this didn't give the benefit of testing an active prototype, so actual deliveries didn't take place until late July. Even so, the challenge was to properly train the crew, and the mechanical components proved unreliable.

In addition, there was the issue of the Allied bombing campaign wreaking havoc on German war production facilities - including the construction of the Type XXI submarine facility. Final assembly of the Type XXI submarine was carried out by the German companies Blohm & Voss, AG Weser and F. Schichau Werften.

The target production target is to have approximately 1,500 service instances - a number that would no doubt devastate Allied naval and naval efforts in the region - and envisages a target production target of three U-boats per week, in turn leveraging the ship's Modular design.

Production and counting

The class did not reach useful strength until late 1944, by which time the German Navy had lost significant positions. By 1945, there were about 62 Type XXI U-boats en route, but with work to do, these were rarely considered combat-ready. By the end of hostilities in May 1945, the German Navy had only four active Type XXIs - not enough to affect the outcome of the war. Only the U-2511 and U-3008 conducted actual wartime patrols, but never claimed Allied tonnage.

The massive Type XXI fleet never materialized for Donitz, and much of the promising technology that made up these ships fell into Allied hands, sparking a global revolution in submarine design that eventually led to the Cold War.

The Type XXI submarine series started with U-2501 and ended with U-3530. Ultimately, two main variants were proposed in the "XXIB" and "XXIC" models, the former with an increase in the number of torpedo tubes to 12 and the latter with 18 torpedo tubes.

Undoubtedly, the addition of forward weapons required a lengthening of the fuselage. In the end, however, nothing took shape.

Post-war period

Some XXIs were in post-war service, these were trophies. The French commissioned U-2518 named "Roland Moillot", and the ship was not in service until 1967. The Soviet Union received four ships of this class, which became the B-27, B-28, B-29 and B-30 in service with the Soviet Navy. U-3017 fell into the hands of the British, who renamed it HMS N41 for a research role (it ran until late 1949).

The United States received U-2513 and U-3008, and the pair underwent extensive testing in operating conditions around the Atlantic Ocean. The former was later sunk as a target in 1951 and the latter was scrapped in 1956.

Lasting

All these fleets benefited greatly from what the Germans did (and tried to do). The GUPPY modernization program in the United States was a direct result of postwar mastery of German technology.

Likewise, several of the Soviet Navy's submarines were directly influenced by their experience with German submarines - a legacy of the Type XXI. Only U-2540 (Wilhelm Bauer) remains as a museum ship and her location is in Bremerhaven.

Specification

Basic

Roles

Dimensions

Weight

Performance

Performance

Armor

Wing