Submarine Type 21 German. German submarines XXI series

The appearance of submarines of the XXI series marked the breakthrough of the Germans in design and construction. These ultra-modern submarines were the first to be mass-produced using nine off-the-shelf modules. Shipyard sections of boat hulls made at different factories in Germany were carefully joined and welded in a minimum time. The theoretical estimate of the time spent on the construction of one submarine of the XXI series was 176 days, while at the assembly shipyard she had to spend only 30 days.

In April 1943, a detailed plan was approved to convert the basic design of the XVIII series (submarine with a displacement of 1600 tons with a Walther turbine and diesel engines) into the XXI series "Elektroboot" with a minimum of changes. On this series, the dual propulsion system was replaced by new turbocharged diesels and improved performance electric motors, along with special "sneak" electric motors, which made it possible to get close to the enemy silently, and in the lower part of the robust hull, instead of tanks for hydrogen peroxide, it became possible to place a large number of batteries, due to which the range of the underwater course of the boat was significantly increased. The end result was a submarine equal in size to the IXD, but with immeasurably increased capabilities. Although the Type XXI submarine had a shorter range and lower surface speed compared to the IXD2, its submerged speed was higher than the surface speed. Able to develop 12 knots under the snorkel and 17.2 knots when moving submerged on electric motors against the 6 and 7 knots of the IX series submarine, respectively, she could dive deeper than the 130 m limit up to a depth of 280 m and go under water for two days at normal speed and eleven days - at low speed without lifting the snorkel.

As the world's first type of true submarine, the Type XXI submarines were equipped for this task. Thanks to the streamlined hull contours and the almost silent course, it was much more difficult for the enemy to detect them. The hull was spacious with many advanced appliances, air conditioning and waste disposal systems, and a refrigerator for storing food supplies. Submarines of the XXI series could wage war while submerged. All six torpedo tubes were placed in the bow of the boat and there was a combat reserve of twenty-three perfect torpedoes with course and acoustic guidance systems. Equipped with hydrophones with a range of up to 50 miles and a sophisticated "Balkon Gerat" echo chamber that made it easy to track, identify and separate group targets while submerged, XXI series boats were designed to carry out attacks without approaching the surface closer than at 50 m. They had all the qualities to turn the tide of the battle for the Atlantic in favor of Germany.

However, for all their perfection, the submarines of the XXI series were not without flaws. The main disadvantage of the boats was a weak design. Hastily manufactured at different factories, the eight hull sections did not fit together properly, and therefore the robust hull could not withstand depth charge explosions at a short distance from the boat and withstand pressure at great depths. The second serious drawback was the imperfection of the hydraulic systems. The piping of many of the boat's hydraulic systems was located between the strong and light hull, so they were susceptible to damage from close bomb explosions and could not be repaired while the boat was submerged. In addition, since external connections could not be made completely watertight, over time, leaks appeared in the pipelines of the hydraulic systems and an oily trace of liquid appeared on the surface. And although individual components of these systems have been improved, the main shortcomings have not been eliminated. The third serious drawback was the inability to use turbochargers. On boats of the XXI series, together with diesel engines, it was supposed to install compressors for pre-compressing the air entering the engine cylinders. However, due to miscalculations in design and construction, the use of compressors was not possible. In this regard, the power of each engine was reduced from 2000 to 1200 hp, which ultimately led to a decrease in surface speed to 15.6 knots and an increase in battery recharge time from one to two hours. It is authentically known that U-2518 was the only submarine of the XXI series captured by the British, which was equipped with turbocharged diesel engines.

A total of 118 submarines of the XXI series were put into operation, but only one of them - U-2511 (commander - Corvette Captain Adalbert Schnee) - went on a military campaign in the Caribbean Sea on May 3, 1945. Another boat, U-3008, was preparing for the first combat campaign in the last days of the war.

DESIGN

Submarines of the XXI series were the first to use prefabricated sections in mass production. At enterprises and plants, often remote from the sea, internal mechanisms and assemblies were assembled in sections of hulls, after which they were sent to assembly shipyards. At the shipyards, sections of the hulls were carefully docked and welded. The structurally robust hull had a modular design and consisted of nine separate sections: aft, electric motors, diesel engines, aft residential, central post, bow residential, torpedo storage, torpedo tubes and cabin.

Submarines of the XXI series were double-hulled; in cross section, the durable case looked like the number "8": the upper and lower parts. The hull of the boat had a completely streamlined contours, without any protruding parts that could increase the drag of the water. Unlike submarines of earlier series, submarines of the XXI series did not have "saddle" tanks and deck armament. Double-barreled 20-mm anti-aircraft guns were built into rotating fairings installed in the front and rear of the conning tower. Periscopes, snorkel, radar masts and other devices were retractable. All controls on the bridge were covered by one fairing with a good hydrodynamic configuration. In general, everything possible was done to reduce drag and increase the speed of the underwater course.

Consideration of the location of the compartments begins with the stern of the boat, in order to avoid confusion in the location of equipment relative to the starboard or port side.

The first compartment in a rugged hull was the aft compartment. There were no stern torpedo tubes on submarines of the XXI series. In the aft compartment, on the port side, there was a small repair shop with a lathe and a bilge pump, and on the starboard side, a latrine. Under the floor of the upper part of the compartment there was an engine oil tank, and in the lower part of the compartment in a strong case there were two trim tanks.

The next from the stern to the bow of the boat was the electric motor compartment. It contained two propeller motors 2 GU 365/30 from Siemens 2500 hp each at 1675 rpm. and two 113 hp "sneak" electric motors. each at 350 rpm. Two fans of the air cooling system were installed above the propeller motors. In front of the compartment near the bulkhead that separated this compartment from the diesel engine compartment, on both sides of the passage were two instrument panels for the submarine's propeller motors. Under the floor of the upper part of the compartment there was a tank of distilled water and a tank of engine oil.

The diesel engine compartment was located next after the electric motor compartment from the stern to the bow of the boat. It contained two 6-cylinder M6V 40/46 turbocharged diesel engines of the Büchi company MAN 2000 hp each at 520 rpm. In the central part of the compartment, above the passage between the engines, there were service tanks of diesel fuel, and in the front of the compartment, on the right and left along the side, there were two fans and air ducts for supplying fresh air to the submarine compartments. Under the floor of the upper part of the compartment there was a diesel fuel collection tank, an engine oil collection tank, an engine oil tank and a used engine oil tank.

The next from the stern to the bow of the boat was the living compartment of the sailors. On submarines of earlier series, the central aisle separated two rows of bunk beds, but on submarines of the XXI series, the beds were placed in four rows, two along each side. In the living compartment of the sailors along each side there were three bunk beds and two three-story bunks separated by a narrow passage, a total of twenty-four beds. In the lower part of the compartment there were batteries of 124 cells in two tiers, including 62 cells of 44 MAL 740 with a capacity of 11300 ampere / hour with a 20-hour discharge in each tier, and battery gas sampling pipelines. The batteries of the upper tier of 62 elements were separated by a narrow passage for their maintenance.

The next after the living compartment from the stern to the bow of the boat was the compartment of the central post with a wheelhouse installed on it. The central station compartment also included a galley located at the rear of the compartment near the bulkhead that separated the central office compartment from the diesel engine compartment. An electric stove was installed in the galley on the port side of the boat, and a pantry for food and a cold store for storing fresh products on the starboard side. The compartment of the central post was separated from the galley by a light bulkhead. In the middle part of the compartment there were shafts for the commander's and anti-aircraft periscopes, the working parts of which were located in the conning tower. In front of the compartment, closer to the bulkhead, there was a large cylindrical tube with an internal staircase leading up to the wheelhouse. To the right of the side in the rear of the compartment near the bulkhead there was a retractable snorkel shaft and opposite it to the right along the side - a control panel for the operation of auxiliary mechanisms, further towards the bow of the boat - a group of valves that regulate the supply of compressed air to the tanks. After them, on the right side, there were electric drives for controlling the stern and bow horizontal depth rudders. Further to the right along the side in the corner of the compartment there was a gyrocompass and in front of the front bulkhead there was a vertical rudder control post, which included an electric rudder control drive, engine control engine telegraph and a gyrocompass repeater. On the left side, in the rear of the compartment, near the bulkhead, there was a retractable mast antenna shaft, along the port side - a group of two compressed air cylinders. Further to the left along the side was a chart table, above which was the indicator of the ultrasonic echo sounder "Atlas", and near the front bulkhead - two oil pumps of the hydraulic system. A distinctive feature of the placement of the equipment of the boat of the XXI series was the presence of a compartment of auxiliary mechanisms, located under the central post. On the right side of the compartment there was a fan of the battery ventilation system, a bilge pump and a piping system; closer to the front of the compartment, a ladder was installed leading to the central post compartment. On the left side of the auxiliary mechanisms compartment there was a group of three compressed air cylinders and an HK 1.5 electric air compressor from Krupp with a capacity of 16 l / min. at a pressure of 205 kg/sq.cm.

The next from the stern to the bow of the boat was the living compartment for officers and non-commissioned officers. To the left along the side, near the bulkhead that separated this compartment from the central post compartment, there was a "cabin" of the boat commander, more spacious than on boats of earlier series. After the "cabin" of the boat commander, on the left side of the board there was a hydroacoustic cabin, behind it towards the bow of the boat - a row of bunk beds along the side and a number of three-tier beds at the central aisle for senior non-commissioned officers, and a row of three bunk beds along the side and a row of two three-tier beds at the central aisle for non-commissioned officers. To the right of the side, near the bulkhead that separated this compartment from the central post compartment, there was a radio room, behind it towards the bow of the boat there was a rather spacious "cabin" of the chief engineer. After the "cabin" of the chief engineer, the submarine officers' berths were located in two rows: a single-tier along the side and a two-tier at the central aisle, and a latrine near the bulkhead that separated this compartment from the torpedo tube compartment. In the lower part of the compartment on the left side under the captain's "cabin", hydroacoustic cabin, senior non-commissioned officers' berths and on the starboard side under the radio cabin and the chief engineer's "cabin" there were batteries of 124 cells in two tiers, including 62 cells each 44 MAL 740 capacity of 11300 ampere/hours with 20 hours of discharge in each tier. In the lower part of the compartment, on the left side under the bunks of non-commissioned officers and on the starboard side under the bunks of officers and latrine, there were also batteries of 124 cells in two tiers, including 62 cells 44 MAL 740 with a capacity of 11300 ampere / hours with a 20-hour discharge in every tier. Both groups of batteries were also equipped with battery gas extraction pipelines and in both groups, the batteries of the upper tier of 62 cells were separated by a narrow passage for their maintenance. The total number of battery cells on a Series XXI submarine was 372 cells, three times the number of battery cells on a Series VII or IX submarine.

The last from the stern to the bow of the boat was the torpedo tube compartment. At the rear of the compartment was a torpedo storage, consisting of three racks for torpedoes along each side. Three torpedoes were stored on the upper and middle racks, and two torpedoes on the lower ones. Another torpedo was stored between the racks at the bottom of the pressure hull. The torpedo ammunition was twenty-three units: seventeen in the torpedo storage, and six in the torpedo tubes. In a light hull under the torpedo storage there were two torpedo replacement tanks. Six torpedo tubes were located towards the bow of the boat, arranged vertically in two rows of three tubes. The supply of torpedoes to the torpedo tubes was carried out using a semi-automatic hydraulic reloading system, which ensured the reloading of the apparatus in 20 minutes. Under the torpedo tubes in the lower part of the compartment in a strong hull were two trim tanks. At the bow of the boat, outside the pressure hull, there was a bow ballast tank and a quick dive tank.

PERFORMANCE AND TECHNICAL CHARACTERISTICS

SERIES XXI SUBMARINES

Any other types of submarines in any country were hopelessly outdated at the same moment when the new brainchild of the Reich designers saw the light. Embodying the best engineering developments of that time, the XXI series boat becomes the most advanced and most dangerous underwater weapon in the world. When moving under water on batteries, she can reach a speed of 17.2 knots, which allows her to pursue any convoys. Moreover, it may not float even under a snorkel for 48 hours at normal speed and 11 days at an economical speed. Thanks to the streamlined hull contours and the almost silent course, the submarine is now invisible to the enemy, while she herself perfectly "sees" her targets and can easily attack from a 40-meter depth. All ammunition - 23 torpedoes (mostly homing) - can be "shot" within half an hour. Potential victims are both transport ships and warships, which before the submariners were afraid like the devil of incense. But that's not all: after an attack, a submarine can descend to a depth of 300 m and maneuver there at high speed: the chance of hitting it with a depth charge is close to zero.

One more detail. With a moderate underwater course of 4-8 knots, it is enough for the boat to surface only once every 2-3 days under the snorkel depth to recharge the batteries for 3-5 hours. Thus, long underwater passages even through areas controlled by the enemy (such as the Strait of Biscay) become practically safe for her. The allies simply have nothing to protect themselves from the high-tech "German".

Device

Submarine XXI series. Cross section of 32.0 sp. (see in the nose)

1 - battery pit; 2 - fuel tank; 3 - tank of the main ballast; 4 - living quarters; 5 - air intake shaft for diesel engines; 6 - cutting fence; 7 - 20-mm anti-aircraft gun; 8 - ship ventilation pipeline; 9 - replacement tank.

Since most of the time the submarine must move under water, the designers tried to minimize its frontal resistance. To do this, the ratio of the length of the hull to the width was reduced, the upper deck was removed, the contours of the wheelhouse were smoothed out, and anti-aircraft weapons were "hidden" in streamlined turrets. All periscopes, snorkel tubes and radar masts are retractable. As a result, compared with the submarines of the IXD / 42 series, the Admiralty coefficient, which characterizes the hydrodynamic qualities of the ship, for boats of the XXI series for a submerged position increased by more than 3 times (156 versus 49).

The strong hull, like on other German boats, is welded. The thickness of its parts, made of St52KM steel with a yield strength of 3400 kg / cm2, reaches 26 mm (our boats of those times with a hull thickness of 12 mm are recalled). The maximum immersion depth is 220 m, the estimated breaking depth is 330 m.

Type XXI submarines had a one and a half hull design. The aft, electric motor, diesel and bow compartments of the robust hull had a cylindrical-conical shape. The battery compartments and the central post, located in the middle part of the robust body and occupying 40% of its length, had a cross-sectional shape close to the number "8" - with a round upper part and a semicircular lower part (see figure). In addition, the upper part of these compartments was additionally divided into two decks. Compartments-shelters, unlike earlier series of submarines, type XXI did not have.

Description of the functions of the compartments, starting from the stern:

1. Aft compartment: rudder drives, high-pressure air tanks, ship workshop.

2. Electric motor compartment: main electric motors and sneaking motors.

3. Diesel compartment: diesel engines and snorkel devices.

4. Aft battery compartment: living and utility rooms of the crew in the upper part (including the galley), battery pits in the lower part.

5. Central post and retractable devices in the upper part, ship devices and replacement tanks in the lower part.

6. Bow battery compartment: living quarters of the crew in the upper part, battery pits in the lower part.

7. Bow compartment: torpedo tubes, spare torpedoes and replacement torpedo tanks.

Power point

The power plant consisted of two in-line (do not believe those who say V-shaped) 6-cylinder four-stroke diesel engines with M6V 40/46 turbines from MAN, each with a capacity of 2000 hp. at 520 rpm. The engines were equipped with a retractable snorkel with radar-absorbing surface coating.

The two main electric motors are GU 365/30 models, each with 2500 hp. at 1675 rpm. In addition to them, the boats had two creeping electric motors, models CV 323/28, which developed a power of 113 hp. at 350 rpm each and connected directly to the propeller shafts through a V-belt drive. Up to a speed of 6 knots, the boat under the creeping engines did not actually produce the noise that was perceptible by the sonar equipment of that time. The batteries of the boats consisted of six groups (and not two, as was the case on previous models) of 62 elements of the 44-MAL 740 type each, their total weight was 225 tons. Such an increase in the power-to-weight ratio significantly increased the resource of the underwater course.

Armament

torpedo

The torpedo armament of type XXI boats consisted of six torpedo tubes of 533.4 mm caliber, which ensured the launch of torpedoes from a depth of up to 30-45 meters. They were placed in the bow of the boat, inside a strong hull. There were three devices on each side (located one above the other).

The regular ammunition load of the boats was 23 torpedoes, including 6 in the torpedo tubes and 17 on racks in front of them. The boats were equipped with an electromechanical fast-loading device, consisting of charging carts moving along rails. The device made it possible, after the first salvo, to reload all 6 torpedo tubes and give a second salvo after 4-6 minutes: a total of 12 torpedoes in 6 minutes; on the famous German "seven" this time would not have been enough to reload even one torpedo tube. Another 6 torpedoes could be fired in 20 minutes.

Artillery

Anti-aircraft armament of Type XXI boats consisted of four 20-mm Flak C / 38 automatic guns. The guns were placed in twin turret mounts, which had light anti-bullet and anti-fragmentation armor, and were located at the ends of the felling fence, being inscribed in its contours. The towers could be controlled both directly and with the help of hydraulic drives from inside the robust hull. Gun ammunition was 3450 rounds.

Detection tools

The basis of the sonar armament was the GHG-Anlage noise direction-finding station, the antenna of which consisted of 144 hydrophones and was located in the lower part of the fore end (under the bow), and the S-Basis sonar station with an antenna installed in the forward part of the cabin fence (field of view up to 100° on each side). Primary detection of targets at distances up to 10 miles was carried out by a noise direction-finding station, and accurate target designation for firing torpedo weapons was provided by sonar. This allowed the boats of the XXI series, unlike their predecessors, to carry out attacks from under the water according to hydroacoustics, without surfacing under the periscope for visual contact.

Habitability

The regular crew of the type XXI submarine consisted of 58 people: 6 officers, 19 foremen and 33 sailors. The sleeping quarters of the submariners were placed on 49 beds, while the living quarters were, as far as possible, freed from the crew members busy with their duties walking through them. Other innovations included an air conditioning system, a desalination plant and a refrigerator (I read somewhere that there was a shower and even a small pool, but I doubt it. I will be in Bremenshafen - I will definitely check).

From project to construction

June 19, 1943 all materials on the XXI series were provided to Grand Admiral K. Dönitz and his staff. The design is highly valued and immediately approved for mass production.

July 6, 1943 the next German shipbuilding program for the period up to 1945 was adopted, which included the construction of boats of the XXI series (102 boats at six shipyards). The first three submarines are to be commissioned in November 1944 by the Bremen shipyard "Deschimag AG Weser". The remaining shipyards will deliver the first boats in March 1945. By May, the volume of their output will have to reach the level of 15 ships per month. Taking into account the time required for the crews to master the "electric boats" and conduct a combat training cycle, the entry of new submarines into the battle for the Atlantic will have to take place ... in 1946!

Dönitz, of course, is categorically against it: the new program provides for too few boats and too late. Grand Admiral addresses the Minister of Armaments Albert Speer. He connects his assistant - Otto Merker, who is developing a technology for accelerated modular construction of boats (not to be confused with sectional: modules are sections that are fully equipped and ready for docking). Modular assembly, typical of the automotive industry, has never been used for such projects.

Advantages of modular assembly:
1. Calculations have shown that the first submarine of the XXI series can be delivered by April 1944, that is, 7 months earlier than with traditional construction methods. Serial production of boats can start immediately after that and reach the level of 30 boats per month.
2. The labor intensity of operations is reduced, and hence the cost of the boat (despite the significant complexity of the design and high resource intensity, the new boat will be slightly more expensive than the boat of the VII series: 5.75 versus 4.7 million Reichsmarks).
2. Orders for the construction of individual sections and equipment can be placed among among machine-building plants throughout the country. Their dispersion will significantly increase the stability of production from air raids, and the assembly of submarines from almost finished sections will attract a large number of shipyards, including small ones, which have never been engaged in underwater shipbuilding before.

However, this technology requires a significant improvement in the quality of construction: the usual "fitting in place" in a modular assembly becomes impossible. In addition, enterprises that assemble sections together become dependent on those who manufacture these sections, and they, in turn, on suppliers of equipment for sections. For these reasons, the introduction of flow-assembly technology will encounter rejection and opposition from shipyards that do not want to break the usual order of work. But thanks to O. Merker's perseverance, shipyards will be forced to agree to a transition to new construction methods.

In September 1943 a special bureau is being created to develop complete technical documentation for the new boat. The staff of the bureau eventually amounted to 1200 people. Working at an accelerated pace, they fulfill their task and already in early December 1943. provide 18400 drawings. November 1, 1943 technology is approved.

The hull of the boat is divided into 9 blocks (the ninth - the superstructure and the cabin fence).
The developed schedule allocates 176 days (less than 6 months) for the construction of each boat:
16 days - metal rolling and transportation of finished sheets to 32 machine-building plants.
40 days - manufacturing of parts and hull structures.
5 days - transportation of hull blocks to the shipyard.
5 days - installation of equipment in blocks with almost 100% saturation with devices and mechanisms, and even with painting.
4 days - transportation of blocks to the assembly shipyard.
50 days - assembly of a submarine from blocks.
- launching.
6 days - outfitting work afloat.
5 days - factory sea trials.

Initially planned to be released by the end of 1944. for a production volume of 38 boats per month. On June 1, 1944, the XXIII series construction program will be reduced to 33 boats per month (with the simultaneous production of XXIII series boats). Then the program will be changed again: now the monthly plan is 10 boats of the XXIII series, 12 boats of the Walter XXVI series, and 22 boats of the XXI series. As a result, instead of 652, there will be 580 boats of the XXI series in the plan.

Impossible plans

Detailed drawings arrive at the shipyard late. Prepared in a hurry, they are incomplete or incorrect in places, which leads to assembly problems. As a result, the launch of the first boat takes place on April 19, 1944. This is U-3501, assembled at the shipyard "Schihau" for the 55th anniversary of Hitler. The boat turns out to be "raw": it will be finalized and handed over to the fleet only in July 1944.

And June 15, 1944. instead of 18 boats, only U-2501 was transferred to the fleet. She was launched on May 12, 1944, but was soon returned to the shipyard for urgent repairs. New boats show their childhood illnesses.

When the propeller motors are reversed, diesel engines begin to suck in outboard water through the gas exhaust system. This was discovered immediately, but managed to damage three boats. When running under diesel engines, the rotation is transferred to the armatures of the electric motors, which leads to a loss of power. Under the snorkel, it is impossible to develop the full power of diesel engines. Snorkels and periscopes have increased vibration above 10 knots. There are problems with battery charging. The system for afterburning hydrogen, which is emitted by batteries, is inefficient (an explosion occurred on the U-3002). When operating at maximum power, electric motors create a powerful magnetic field, which nullifies protection against magnetic mines. Hydraulics failed.

Only at the end of 1944. (November-December) the first tests at full speed are carried out. Boats show surface and underwater speeds less than estimated. After some modifications, their characteristics have been improved. In December 1944 28 new boats were built. However, Allied air raids knock the Germans out of all plans.

So, several boats were destroyed in the docks of Hamburg. In February 1944 the main suppliers of diesel engines and electric motors - MAN and Siemens - as a result of the bombing disrupt the supply of engines. Part of the assembly lines have to be moved from the shipyards to the reinforced concrete bunker for submarines "Valentin" near Bremen. In the spring of 1945 two aerial bombs damage the construction positions of the bunker, and the assembly of boats becomes impossible.

At the Blom und Voss shipyard in Hamburg, 262 submarines from U-2501 to U-2762 were supposed to be assembled, but only 47 were actually delivered.
In Bremen, the AG Weser shipyard was supposed to assemble 100 units from U-3001 to U-3100, but 43 were assembled.
The Vulkan-Werke firm in Vegesack was supposed to assemble 195 units from U-3101 to U-3295, but their completion was partially stopped due to lack of funds, and partially they did not even begin.
Firm "Schichau-Werft" in Danzig was supposed to assemble 95 units from U-3501 to U-3595, but collected 29. U-3531 - U-3571 were never launched, and assembly U-3572 - U-3595 was not started, although all the preparatory work was carried out.

A total of 119 submarines of the XXI series were built and delivered to the fleet. They are quickly brought to mind. The first required level of combat readiness reaches in March 1945 the boat U-2511. In early May, another 12 boats should hastily complete combat training. It is assumed that they will move from the rear bases of the Baltic and North Seas to Norway (where U-2511 is already located) in order to break into the ocean from there.

April 30, 1945 U-2511 under the command of the famous ace Adalbert Schnee goes on a military campaign from the port of Bergen (Norway) to the western Atlantic. On May 1, off the east coast of Great Britain, moving at periscope depth, she meets with a group of British submarine hunters, but thanks to effective navigational aids and an advantage in speed, she leaves them.

On May 4, Grand Admiral Dönitz orders the cessation of hostilities. U-2511 lays down on the reverse course. In the area of ​​the Faroe Islands, she meets a group of British ships, incl. the heavy cruiser Norfolk and several destroyers. The boat, moving on the sneak motors, goes into position to attack the cruiser, but the commander does not give the order to open fire. U-2511 goes into hiding, and remains unnoticed by the British. Later, the boat commander will have the opportunity to talk with the officers who were on the Norfolk cruiser. They will be shocked to learn that they were in mortal danger at that moment from a boat that was only 500 meters away from them.

On May 3, another new boat - U-3008 - left Wilhelmshaven and headed for Norway. On the same day, passing through the Skagerrak off the coast of Norway, she attacks an unidentified large British ship, but, like U-2511, she abandons her intentions. The commander of the boat, H. Mansek, was not mistaken: the next day the war officially ended for him.

It is no exaggeration to say that if it were not for delays in construction, these boats would have revolutionized naval warfare. But the miracle didn't happen. About a dozen new submarines, which tried to leave for Norway in the last days of the war, were sunk in the Baltic straits by Allied aircraft. 17 boats capitulated. 85 boats scuttled by crews.

post-war period

boat museum in Bremenshafen

Everything that was left after Operation Deadlight was divided between the USA, the USSR and England. The share of Great Britain from 8 boats of the XXI series included U-25I8 and U-3017. Britain soon handed over the U-25I8 to France. The boat was manned by a French crew and was part of the French fleet under the name "Roland Morillot" until 1968.

In November 1945 the British brought submarines to Liepaja to be transferred to the Soviet Union. Among them were four submarines of the XXI series: U-2529, U-3035, U-3041 and U-3515. All of them became part of the Baltic Fleet and served there as combat submarines until 1955. After that, the boats were used as blockships (U-3515), floating charging stations (U-2529 and U-3035) and an experimental submarine (U-3041). In 1958-1959. all electric boats, except U-3515, were scrapped. U-35I5 was used as a training station until 1972, having thus existed for 27 years.

In addition to these boats, our troops captured in Danzig on the stocks of the Schichau shipyard 20 unfinished submarines of the XXI series and a significant number of blocks prepared for the assembly of boats. In the summer of 1945 submarines with numbers from U-3538 to U-3557 were launched and transferred to the USSR. They were supposed to be completed according to project 614 using domestically produced components instead of the missing equipment. But under pressure from former allies, the Soviet leadership abandoned these plans. U-3538 - U-3540, which were in the highest state of readiness, sank in August 1947 in the Baltic Sea 20 miles northwest of the Ristna lighthouse. Other boats in 1947-1948 handed over for disassembly.

The Americans took U-2513 and U-3008 for study. They, too, conducted a thorough study of the trophies at Key West in Florida. U-3008 was decommissioned in 1947 and equipment from the boat was used to repair U-2513. In July 1949 U-2513 was removed from the US Navy. For some time, both boats were laid up, and then used as targets for testing naval weapons. U-2513 was sunk in October 1951 and U-3008 by July 1954.

In 1957 in the Flensburg area, the Germans raised the flooded submarine XXI series U-2540. The Kiel shipyard Howaldtswerke undertook to restore it to its original form. But in the autumn of 1958 it was decided to convert the U-2540 into an experimental submarine for testing new equipment. Refitted for new purposes, U-2540 became part of the Bundesmarine in September 1960, under the name "Wal" (type 241). In 1984 the boat under the name "Wilhelm Bauer" was installed in the Museum of German Navigation in Bremenhafen (near Bremen). There she is to this day.

Three more type XXI boats, U-2505, U-3004 and U-3506, were considered missing, but in 1987 they were found in the blown up Hamburg bunker Elbe II. All three boats are in poor technical condition. U-3506 is crushed and damaged by fallen concrete floor beams.

ahead of time

German "electric boats" made a revolution in their field, dividing all submarines into ships of two eras - before the creation of the XXI series and after it. The post-war development of boats in the USSR, England and the USA technically largely repeated the German boat, using it as a prototype. We note the following related projects:

USSR - project 611, project 613;

Sweden - type "Hayen";

Great Britain - modernization of boats of type "T";

France - type "Narwhal";

USA - type "Tang" (1949-1952).

The principles laid down in the XXI series have been improved, but in essence have remained the same to this day. As for the modular production of submarines, this experience of the Germans has not been repeated by any of the countries of the world.

Submarines of the XXI and XXIII series were the most advanced submarines created during the Second World War. Significant depth of immersion and long range, strong armament and excellent hydrodynamic characteristics, noiselessness and unprecedented secrecy. The complex of these qualities turned Nazi submarines into extremely dangerous opponents. But they appeared too late to affect the course of hostilities in the open sea.

Ocean submarines of the XXI series.

In September 1943, a special design bureau Ingenieurbüro Gluckaüf was organized to issue design documentation and coordinate the work of enterprises involved in the construction of boats and the supply of equipment. One of the initiators of the creation of the submarine of the XXI series, H. Elfken, was appointed its director. By the end of 1943, the staff of the bureau included 1,200 people, whose working day lasted 12 hours with three days off per month. It is located in the center of Germany in the bombardment-safe mountain towns of Blankenburg (design departments of the bureau) and Halberstadt (departments for coordinating work and managing the serial submarine construction program). Operational teams of bureau specialists were available at all shipyards and large supplying enterprises involved in the creation of submarines of the XXI, XXIII and XXVI series.

In early December 1943, the bureau basically completed the development of design materials for the XXI series submarines, releasing 18,400 working drawings in less than 4 months. In Blankenburg, a life-size wooden model of the submarine was made, on which the layout of the premises was worked out, the sequence of equipment installation was specified, templates were removed for the preliminary manufacture of all pipelines that had a diameter of more than 30 mm.

According to the documentation developed in the bureau, the hull of the XXI series boat was divided into 9 blocks. Hull structures ("raw" sections) for each of them were manufactured at four enterprises, most of which were located in central Germany. As a rule, these were machine-building enterprises that were not previously associated with shipbuilding. For example, the hull structures of the fore end (block No.: 8) were manufactured by the sapper equipment plant. Each enterprise (except one) specialized in the production of a single type of blocks. Thus, 35 enterprises were involved in the manufacture of hull structures. Unlike the others, block No: 9 (superstructure and fencing of the felling) was made completely at once, bypassing the saturation phase. In the manufacture of hulls, welding was widely used. The quality of the welded seams of the pressure hull was checked by their 100% radiography.

Orders for the production of hull structures were issued already in August 1943, and then the order of their manufacture was subject to a strict schedule. His motto was “just in time”, allowing neither late (which is understandable) nor early. The latter condition was intended to eliminate the risk of destroying sections during storage at shipyards subjected to air raids.

The final assembly and delivery of the boats of the XXI series were to be carried out by 3 assembly shipyards: Blohm & Voß (Hamburg), Deschimag AG Weser (Bremen) and Schichau (Danzig). Blocks with mechanisms and equipment installed in them were lined up on the slipway one after another. The accuracy of the installation of the blocks was controlled by two light lines of the bow and stern compartments. To do this, holes of small diameter located on the same axis were drilled in the bulkheads. When connecting the blocks through these holes, light should have been visible in the central post from the end compartment. After connecting and welding the blocks, the downhole parts of the light hull were installed, covering the areas of the mounting joints of the strong hull, the shafting was installed, the pipelines were connected and the main cables were spliced, periscopes, antennas, a snorkel were installed, battery cells were loaded.

The boat was painted and launched into the water. Artillery weapons and small equipment were mounted afloat.

The introduction of the new technology made it possible to significantly (by 20-40% than that of submarines of the IXD2 series close to them in terms of displacement) to reduce the labor intensity of the construction of submarines of the XXI series. In terms of their cost (5.75 million marks), the submarines of the XXI series practically did not differ from the boats of the medium displacement of the VIIC series.

Initially, by the end of 1944, it was planned to reach the rate of monthly delivery of thirty-eight submarines to the fleet. However, the parallel deployment of the XXIII small boat building program reduced this figure to 33 boats per month. In 1944, the pace of construction underwent a second adjustment and was reduced to 22 submarines per month in connection with the inclusion of medium boats of the XXVI series in the shipbuilding program of G. Walter.

Despite the high pace of work, O. Merker's plans for the delivery of the first submarines of the XXI series in April 1944 did not materialize. The schedule was disrupted both due to failures in the supply of equipment and the lag in the readiness of units, and due to the losses caused by the bombing of Allied aircraft. As a result, the launch of the first boat of the XXI series took place in Danzig only on April 19.

During the tests of the head submarines of the XXI series, the shortcomings of the project began to be revealed, which were mainly due to the rush to deploy construction and insufficient development of the newly created equipment. True, the first six submarines at each shipyard were originally supposed to be used as experimental ships for testing, identifying comments, working out the design and training crews.

It turned out that the boats of the XXI series have a number of serious shortcomings in the design decisions for the power plant. When running under diesel engines, rotation was also transmitted to the armatures of the main electric motors, which led to an unproductive loss of power. In the mode of movement under the "snorkel" it turned out to be impossible to develop the full power of diesel engines. In addition to problems with the design of the snorkel itself and the high noise of the compressors, tests revealed increased vibration of the snorkel and periscopes at speeds above 10 knots (16 km / h), the required speed is 12 knots. The threat of damage to the mast-lifting devices and the inability to monitor the environment made it necessary to limit the speed of the boat under the "snorkel" to six knots.

When charging series-connected groups of batteries, the least discharged group was charged first, and after it the more discharged ones. As a result, in real combat conditions, with a limited charging time, it turned out to be almost impossible to fully and evenly charge all battery groups.

In the submerged position, the boats of the XXI series also failed to reach the design speed and obtain the required cruising range. Submarine U-3507 managed to develop a speed of 17.2 knots. At the end of November, the same boat, with the area of ​​scuppers reduced by one third, managed to develop a speed of 16.8 knots and maintain it for 20 minutes; for an hour, the submarine U-3507 maintained a speed of 16.5 knots (26.5 km / h). This area of ​​scuppers was also recommended for other boats of the XXI series. At the same time, the achieved full underwater speed was 1.5 knots less than the calculated one. Under the sneaking motors, an estimated speed of 6.1 kt (9.6 km/h) was obtained with a propeller speed of 123 rpm. However, in this mode, the boat was almost impossible to detect.

U-2506 dived to a depth of 220 m without any problems, exceeding the design test depth by 10%. In a real-combat situation, a submarine submerged to a depth of 200 was not detected and its defeat by means of ASW could only be accidental.

Assembly yards and boats that were on stocks and in completion afloat were subjected to bombing. In July 1944, U-2503 was damaged in Hamburg, U-3009 in Bremen, and U-2529 and U-2532 were damaged in November. The actions of the British aviation became especially fierce and purposeful at the end of 1944.

From February 1944 until the end of the war, about 140 air raids were carried out on the Siemens Schukert Werke AG and MAN enterprises, shipyards and submarine rear bases. It was possible to destroy 17 and damage more than 20 submarines of the XXI series.

Of the nearly 180 new ocean and coastal "electric boats", very few were in combat readiness by the end of the war and had crews who had completed a full course of combat training. The reasons for such a long delay in the introduction of ships into combat were the lack of development of their equipment and adopted technical solutions, which were revealed during the tests and required a long fine-tuning. The current situation has become the reverse side of the rush to create a submarine. In addition, the technical complexity and novelty of the methods of combat use of ocean-going boats of the XXI series required a long time for the training of their crews.

Among the submarines of the XXI series in March-April 1945, only one U-2511 submarine was prepared for combat operations. Only on 30 April was U-2511 able to leave Bergen. On May 4, when the order was received to end the submarine war, she was at the crossing in the Faroe Islands. U-2511 became one of the few among the 45 German submarines that were at sea in early May, which immediately obeyed the order of its commander-in-chief. Nevertheless, on the same day, having found a British cruiser guarding the destroyer, the "electric boat" took up an attack position, but did not shoot and disappeared, and remained undetected.

Another boat of the XXI series in the same days had combat contact with the enemy. It was U-3008 under the command of Lieutenant Commander H. Mansek, which left Wilhelmshaven on May 3 and was heading for southern Norway. In the Skagerrak Strait, she discovered a large British ship and tried to attack it. However, given the upcoming surrender, the commander of U-3008, like A. Schnee, refused to use weapons.

Small boats XXIII series.

Proposals for a small "electric boat" were made by H. Elfken to Grand Admiral K. Doenitz in June 1943 during the consideration of the draft XXI series. The commander-in-chief approved the idea, but set two conditions: the boat must be armed with standard seven-meter torpedoes (instead of special shortened torpedoes 5.5 m long for small submarines of the XXII series) and must be adapted for transportation by rail. This was the start of the development of the project, which received the designation XXIII series. A little more than a month was allotted for the design work carried out under the guidance of A. Grim.

At the beginning of August 1943, the draft submarine of the XXIII series was ready. The power plant of the coastal boat was built on the same principles as the ocean submarine of the XXI series. But in terms of weapons and means of observation, a small displacement did not allow many technical innovations to be applied in the project, and in this respect, the submarine of the XXIII series retained the features of traditional boats.

As on the submarine of the XXI series, the drive to the shafting from the main engines was carried out through a reduction gear, and from the creeping HED - using a text-line transmission. The boat was equipped with a "snorkel", which increased its stealth when charging the battery and at transitions in the periscope position under a diesel engine.

It was expected that in a submerged position, the boat of the XXIII series would reach speeds of up to 13 knots, which was 1.75-1.8 times more than other small submarines. In terms of cruising range - 2500 miles, the "electric boat" of the XXIII series was 3-5 times superior to the small submarines of the II series. The resulting surface range was considered sufficient for a coastal submarine.

The submarine of the XXIII series was armed with only two torpedo tubes for seven-meter torpedoes. Their charging was carried out in the base through the front covers, for which it was necessary to create a trim to the stern of about 5 °. The boat did not have spare torpedoes and anti-aircraft artillery weapons. The small ammunition load of torpedoes was perhaps one of the most serious shortcomings. Having two torpedoes, the “electric boat” could, as a rule, perform only one attack, after which it had to return to the base even without weapons for self-defense. As a result, the transition time could exceed the duration of the submarine's stay in the combat area. In addition, it is known that the submarines suffered the greatest losses precisely on the transitions from the base to the area of ​​\u200b\u200bthe combat position and back. The actual probability of destruction could be reduced due to the high secrecy of these submarines.

Unlike the boats of the XXI series, the small "electric boat" was equipped with a reduced set of surveillance equipment. The primary search for targets was carried out using the GHG-Anlag noise direction finding station. The submarine of the XXIII series did not have an active sonar, and the target designation data necessary for the use of torpedo weapons could be obtained, as on previous submarines, only visually using a periscope. The boat also did not have search radar weapons, which did not particularly reduce the combat capabilities of the submarine. Type XXIII boats were used for attacks close to enemy bases. The ships of the convoy no longer guarded the transports and boats-sea hunters, whose radar and sonar were not distinguished by special power and selectivity, had to withstand attacks from under the water.

Since the end of 1944, the lining of the hulls of XXIII series boats with the Alberich anti-sonar coating, which received its name in honor of the owner of the invisibility cap from the legend of the Nibelungs, began. The coating consisted of rubber sheets 4 mm thick with internal air cavities (horns) and provided a reduction in the level of the reflected echo signal. By the beginning of 1944, the specialists of the IG Farbenindustrie concern had managed to solve the technological problems of coating.

Submarines of the XXIII series were capable of sinking extremely quickly. The immersion system has been extremely simplified. It was enough to open the ventilation valves, and the kingston tanks of the main ballast (TsGB) in 20 seconds. were filled with water. On the move, when using horizontal rudders, complete immersion occurred in just 14 seconds. In this case, the boat usually had a steep trim on the bow. This feature, useful in combat conditions, required the crew to be especially precise in performing the dive maneuver. The working depth of immersion was 100 m, the destructive depth was 250 m, i.e. boats could normally dive up to 150 m.

Under the creeping HED, the submarine of the XXIII series showed a speed of 4.8 knots (7.7 km / h) and could travel up to 215 miles with an economic speed of 2.5 knots. At the same time, the noise of the boat was so low that it was practically impossible to detect it by the ship's direction-finding stations. During the tests, it turned out that under the "snorkel" submarines of the XXIII series can go at a speed of about 11 knots (17.6 km / h), that is, faster than on the surface.

The little killers were virtually undetectable once they were in position. The boats of the XXIII series had one more indisputable advantage - a very low cost, it was supposed to build up to 20 boats of the XXIII series every month, which was equivalent in terms of costs to 5-6 ocean-going submarines. The main builder was identified as "Deutsche Werft" in Finkenwerder. In August 1943, this shipyard was given a contract for the construction of 140 submarines of the XXIII series.

However, this time the original plans were violated. The reasons for the failure became standard - delays in the manufacture and supply of equipment, the difficulty of mastering new technology, losses from allied air raids. In addition, during the construction, a serious miscalculation of the designers was revealed - the actual load of the boats exceeded the calculated one. To compensate for the overload and increase buoyancy in the area of ​​​​the bow rooms, it was necessary to cut in an additional section 3A 2.2 m long, which received the name “Elfken section” “in honor” of the culprit of the miscalculation, the director of the Glückauf bureau. And although the displacement increased by almost 20 tons (about 10%), as a result of such embarrassment, the conditions for placing the battery and living quarters have improved markedly. The block method of design and construction made it possible to survive this metamorphosis without significant structural problems.

As Germany continued to lose its industrial potential, this shipbuilding program was also adjusted. Like the entire economy of the Third Reich, it shrank like shagreen leather. After the loss of the Ruhr, the shortage of steel became acute, which was primarily directed to the manufacture of tanks. There was a lack of skilled labor, and air raids were causing more and more damage. The new focus of the September program was the gradual transfer of the assembly of XXIII series submarines from Deutsche Werft to shelter bunkers located in the Kiel region, where the construction of boats was to be carried out by Germaniawerft. In the shelter "Kilian" it was supposed to be installed in blocks of equipment and mechanisms, and in the shelter "Conrad" - to conduct a block assembly. Since May 1945, it was planned to build submarines of the XXIII series only in protected reinforced concrete shelter bunkers.

In contrast to the oceanic "electric boats", the simpler design and the usual tactics of the combat use of the XXIII series submarines allowed the crews to master them relatively quickly. Therefore, small "electric boats" took a real part in the hostilities. Beginning in February 1945, they made 10 trips from the Norwegian North Sea bases of Kristiansand and Stavanger to the east coast of Britain and the mouth of the Thames. Their actions were quite successful. Small "electric boats", which had only 2 torpedoes each, sank 4 cargo ships and damaged several ships, but they themselves had no losses. Characteristically, the duration of the cruises of the XXIII series boats, as a rule, reached a month, which was three times the design autonomy. The commanders spoke of them as follows: “...this is the perfect boat for short trips near the coast. It is fast, has good maneuverability, and is easy to manage. The small size of the boat makes it difficult for the enemy to detect it. He can only assume the presence of a boat, but it is difficult to establish its exact location..

German submarines of the XXI series, without exaggeration, are the best ships of this class in the world of that era. In all the leading naval powers, they became a role model. What was revolutionary about them? The creation of submarines of the XXI series began in 1943. Then the tactics of "wolf packs", based on group night attacks of submarines that operated from the surface, ceased to bring results. Boats chasing convoys on the surface were detected by radar and subjected to preemptive counterattacks. Submarines, forced to operate from a surface position, as they were inferior to convoys in speed and had a limited supply of energy resources, were doomed to lose.

The device of the XXI series submarine:
a - longitudinal section; b - location of propulsion motors; c - deck plan.
1 - vertical steering wheel; 2 - fairing hydroacoustic station (GAS) "Sp-Anlage"; 3 - life raft containers; 4 - creeping electric motor; 5 - device for diesel operation under water ("snorkel"); 6 - diesel; 7 - living quarters; 8 - air supply shaft for diesel engines; 9 - fenders of the first shots; 10 - 20-mm artillery mount; 11 - gas exhaust shaft; 12 - retractable radio antenna mast; 13 - radar station antenna; 14.15 - commander's and navigational periscopes; 16 - fairing GAS "S-Basis"; 17 - torpedo loading hatch; 18 - spare torpedo; 19 - torpedo tube; 20 - fairing GAS "GHG-Anlage"; 21 - battery pits; 22 - propeller shaft gearbox; 23 - rowing motor; 24 - cabin hydroacoustics; 25 - radio room; 26 - central post; 27 - stabilizer; 28 - stern horizontal rudders

The solution to the problem lay in a radical improvement in the quality of the submarine, and precisely the quality of the submarine. And this could only be ensured by the creation of a powerful power plant and high-capacity energy sources that do not require atmospheric air. However, work on new gas turbine engines was slow, and then they made a compromise decision - to create a diesel-electric submarine, but focusing all efforts primarily on achieving the best performance of diving elements.

A feature of the new boat was the use of powerful electric motors (5 times more than the previous large submarines of the IX series, which had the same displacement) and batteries with a tripled number of element groups. It was assumed that the combination of these proven solutions and perfect hydrodynamics would provide the submarine with the necessary underwater qualities.

The submarine was originally equipped with an advanced device for diesel operation under water "snorkel". This allowed the boat, being under the periscope and sharply reducing its radar signature, to charge the battery, making transitions under diesel engines. The approach of anti-submarine ships conducting the search was detected by a submarine using the antenna of the receiver of signals from operating radar stations installed on the "snorkel". The combination of these two devices on one retractable mast made it possible to warn divers in a timely manner about the appearance of the enemy and to evade him by diving into the depths.

The total weight of the battery installation was 225 tons, and its share in the displacement reached 14%. In addition, the capacity of the elements previously developed for the IX series submarines was increased by 24% in a two-hour discharge mode or by 18% in a twenty-hour discharge due to the use of thinner plates. However, at the same time, the battery life was halved - from 2-2.5 to 1-1.5 years, which approximately corresponded to the average "life expectancy" of submarines participating in hostilities. In this regard, the boats of the XXI series were considered by the designers as wartime ships, as a kind of "expendable" with a relatively short life cycle, the same as a tank or aircraft. They did not have excess resources, typical for peacetime ships that have been in service for 25-30 years.

The placement of such a powerful battery became possible only thanks to the original shape of a durable case with cross sections in the form of a "eight". On boats of the XXI series, the battery pits occupied about a third of the length of the strong hull and were located in two tiers - in the lower segment of the "eight" and above it, with a central passage between the batteries.

The robust hull of the XXI series submarine was divided into 7 compartments. But, unlike the previous boats of the VII and IX series, it refused to allocate shelter compartments with spherical bulkheads of increased strength, which, as a rule, were the end compartments and the central post compartment. The experience of the war showed that in combat conditions the concept of rescuing submariners from shelter compartments is practically unrealizable, especially for boats in the ocean zone. The rejection of shelter compartments made it possible to avoid technological and layout costs associated with spherical bulkheads.

The contours of the stern end, adopted to achieve high speed qualities, did not allow the placement of stern apparatus. But this did not affect the methods of using new submarines. It was assumed that, having discovered the convoy, she should take a position ahead of him, and then, approaching in a submerged position at the maximum possible speed, break through the guards and take a place under the ships inside the warrant (the relative position of the ships at the sea crossing and during the battle). Then, moving along with the convoy ships at a depth of 30-45 m and hiding behind them from anti-submarine ships, the boat, without floating up, carried out attacks with homing torpedoes. Having shot the ammunition, she went to great depths and, with a low noise move, dodged aft from the convoy.

Artillery weapons were intended only for air defense. Two twin 20-mm gun mounts were located in turrets, organically inscribed in the contours of the felling fence. Unlike previous ships, the submarines of the XXI series were for the first time equipped with a fast-loading device, which made it possible to reload all torpedo tubes in 4-5 minutes. Thus, it became technically possible to fire with full ammunition (4 volleys) in less than half an hour. This became especially valuable when attacking convoys that required a large amount of ammunition. The depth of torpedo firing was increased to 30-45m, which was dictated by the requirements for ensuring safety from ramming and collisions when the boat was in the center of the warrant, and also corresponded to the optimal operating conditions for surveillance and target designation when performing non-periscope attacks.

The basis of the sonar armament was a direction-finding station, the antenna of which consisted of 144 hydrophones and was located under a drop-shaped fairing in the keel of the bow, and a sonar station with an antenna installed in the forward part of the wheelhouse fence (field of view up to 100 ° on each side). Primary detection of targets at distances up to 10 miles was carried out at a noise direction finding station, and accurate target designation for firing torpedo weapons was provided by sonar. This allowed the boats of the XXI series, unlike their predecessors, to carry out attacks from the supply according to hydroacoustics, without surfacing under the periscope for visual contact.

To detect the most dangerous opponents - anti-submarine aircraft - the boat was armed with a radar station (RLS), which was used only on the surface. Subsequently, on boats scheduled for delivery to the fleet in the summer of 1945, it was planned to install a new radar with an antenna on a retractable mast that rose in the periscope position.

Much attention was paid to the hydrodynamic qualities. The shape of the hull provided low resistance in a submerged position, but at the same time, it also made it possible to maintain good surface seaworthiness. The protruding parts were reduced to a minimum, they were given a streamlined shape. As a result, compared with the previous large submarines of the IXD / 42 series, the Admiralty coefficient, which characterizes the hydrodynamic qualities of the ship, for boats of the XXI series for a submerged position increased by more than 3 times (156 versus 49).

The increase in underwater speed required an increase in the stability of the submarine in the vertical plane. For this, horizontal stabilizers were introduced into the composition of the stern plumage. The applied scheme of the stern plumage turned out to be very successful. In the post-war period, it became widespread and was used on a number of diesel and then nuclear submarines of the first generation.

Hydrodynamic perfection favorably affected the underwater noise of the ship. As shown by post-war tests conducted by the US Navy, the noise of the XXI series boats when moving under the main electric motors at a speed of 15 knots was equivalent to the noise of American submarines traveling at a speed of 8 knots. When moving at a speed of 5.5 knots under the creeping electric motors, the noise of the German submarine was comparable to the noise of American boats at the slowest speed (about 2 knots). In the low-noise mode of movement, the boats of the XXI series were several times superior in the range of mutual sonar detection to the destroyers guarding the convoys.

Special measures were envisaged to significantly improve the habitability of new submarines. Realizing that in conditions of long-term cruising, the combat capability of a submarine largely depends on the physical condition and well-being of the crew, the designers applied such novelties as air conditioning and a water desalination plant. The system of "warm" beds was liquidated, and each submariner received his own individual sleeping place. Favorable conditions were created for the service and rest of the crew.

Traditionally, German designers paid great attention to ergonomic factors - the convenience of the crew, the most effective combat use of technical equipment. The degree of thoughtfulness of these "details" is characterized by such an example. The flywheels on the valves of ship systems, depending on the purpose, had their own shape, different from others (for example, the flywheels of the valves on the overboard lines had handles with a ball end). Such, it would seem, a trifle allowed submariners in an emergency, even in complete darkness, to act unmistakably, by touch controlling the valves and blocking or starting up the necessary systems.

Before the end of World War II, German industry for 1944-1945. handed over to the fleet 121 submarines of the XXI series. However, on April 30, 1945, only one of them went on its first combat campaign. This is explained by the fact that after the release of the submarine from the factory, 3-month tests were envisaged, and then another 6-month course of combat training. Even the agony of the last months of the war could not break this rule.

U-21: The Phantom Menace
Text: Margarita Safonova

German submarines of the U type made a real world revolution in the tactics of naval combat. The story began in 1906. It was then that the first submarine of this type - U-1 was launched. However, success did not come immediately. Most of the submarine models were imperfect, and the only way to check all the shortcomings was in practice. U-9 and other models failed kerosene engines, U-15 was easily sunk by the British, and only U-21 became the first submarine in world history to sink a cruiser.

Technical characteristics of the underwater "monster"

The submarine U21 belonged to the Sh 9 series and, together with two other boats of the same project - U20 and U22 - was built in Danzig. The boat was launched on February 8, 1913. Instead of the kerosene engines previously used in all German submarines, the U21, like the rest of the boats in the series, was equipped with diesel engines mass-produced by the German industry. Submarines of the U19 series took an active part in the First World War.

Captain Otto Herzing

In history, this name is mentioned much less frequently than the name of Herzing's namesake Otto Weddingen. However, we must not forget that it was the commander of U-21, Lieutenant Commander Otto Herzing, who was the first to succeed. On September 5, 1914, the German submarine U-21 under his command destroyed the English armored cruiser Pathfinder (“Pathfinder”).

Despite the fact that U-21 was rocking hard due to the storm, the torpedo hit the small cruiser under the forward tube. The bow of the ship exploded, engulfed in flames, the stern rose out of the water, the stricken ship tilted and went to the bottom in 4 minutes, sinking with its bow along with a crew of 259 people.

From the memoirs of U-21 captain Otto Herzing:

“My partner looked through the periscope, and I stood with bated breath. The war giant's propellers were directly above us. And we moved almost by touch.

Torpedoes! Fire! I screamed, and my heart almost jumped out of my chest.

There was a terrible explosion, a huge black cloud of smoke appeared on the surface of the sea. I saw that the torpedo had hit its target, and since we were directly under the ship, the possibility of a double catastrophe was almost inevitable. It was reckless, I agree, but I had to take the risk.

Full speed ahead! - I commanded and we dived as deep and swam as fast as it was possible. The crazy maneuver saved us. When I dared to look through the periscope, we were already far from the crash site. (Report of the German captain Herzing dated May 25, 1915.)

Herzing's shot opened a new page in the history of naval warfare. And U-21 was lucky enough to turn that page. Now surface ships (both military and commercial) have ceased to feel their invulnerability from attacks from under the water.

This drawing shows a cross-section of one of the 380 German U-boats that participated in the First World War. Shown here is the U-21 model. The boat U21 sank on February 22, 1919 in the North Sea while crossing from Germany to Great Britain.

Statistics
In total, during the First World War, 600 submarines of the warring states sank 55 large warships (battleships and cruisers), 105 destroyers, 33 submarines.

During World War II, Germany built 1,157 submarines until 1945. German submariners sank 2,603 ​​Allied warships and transport ships with a total displacement of 13.5 million tons. As a result, 70 thousand military sailors and 30 thousand sailors of the Allied merchant fleet died.

During the years of World War II, 789 German submarines (according to Anglo-American data) or 651 (according to German data) were destroyed.