Class VII submarine

VII class
U 995 (model type VII C / 41) in Laboe (2004)
Overview
Type	Hunting submarines
units	A total of 705 User: Kriegsmarine   All boats  Royal Navy U 570 / HMS graph  Norway U 926 / KNM Kya U 995 / KNM Kaura U 1202 / KNM chin  French Navy U 471 / Le Millé U 766 / Le Laubie Armada Española U 573 / G-7  Soviet Navy U 250 / ТС-14 U 1057 / Н-22, С-81 U 1058 / Н-23, С-82 U 1064 / Н-24, С-83 U 1305 / Н-25, С-84
Shipyard	Deschimag / AG Weser , Bremen Blohm & Voss , Hamburg Howaldtswerke , Hamburg Stülcken-Werft , Hamburg Krupp Germaniawerft , Kiel Deutsche Werke , Kiel Kriegsmarinewerft , Kiel Flender-Werke , Lübeck AG Neptun , Rostock Stettiner Oderwerke , Stettin F. Schichau , Danzig Danziger Werft , Danzig North Sea Works , Emden Kriegsmarinewerft Wilhelmshaven Flensburger Schiffbau-Gesellschaft AG Weser - Seebeck works Bremer Vulkan - Vegesacker Werft
Order	1933
period of service	1936–1970 (U-573-G7)
Whereabouts	Only one boat Museum ship: U 995 All others sunk or scrapped
Technical specifications

The U-Boot-Klasse VII , officially called Type VII , was a series of submarines of the German Navy during World War II . Emerged from the First World War -structures UF and UG and experience with type I and type II it was the submarine class most frequently produced of history; it also sunk more space in terms of ship tonnage than any other type. More than 700 units were put into service. Another 160 were planned, but their construction was canceled in favor of the technically superior Type XXI .

The Type VII was a single-hull ocean-going boat, the characteristic feature of which was the external fuel bunker, the so-called saddle tanks in the side bulges of the hull. In contrast to the Type IX deep-sea boats and the Type II coastal submarines , they were called "Atlantic boats ". They reached the greatest diving depth of all boats built during the Second World War (apart from the class XXI, which was not put into service until 1944), which in practice went well beyond the shipyard guarantee. The boats had a high attack power and good performance characteristics with relatively small dimensions, while sacrificing quality of living.

Series

Type VII A

This type of submarine was developed in the years 1933–1934. It was significantly larger than the Type II and had four bow torpedo tubes and one stern torpedo tube. This stern torpedo tube was attached outside the pressure hull, which meant that reloading under water was not possible. Up until the first years of the war, these submarines were equipped with a 8.8 cm cannon in front of the tower. The cannon was later abandoned, especially as the Allies' increasing air superiority made surface fire too risky.

Technical specifications

• Displacement: Total displacement 915 m³
  • over water 626 tons
  • under water 745 tons
• Length: total 64.5 m, pressure hull 45.5 m
• Width: total 5.85 m, pressure hull 4.7 m
• Draft: 4.4 m
• Height: 9.5 m
• Drive:
  • over water: two 6-cylinder MAN M6V40 / 46 diesel engines with a total of 2310 hp (1700 kW)
  • under water 750 PS (560 kW)
• Speed:
  • over water 17 knots (31 km / h)
  • under water 8 knots (15 km / h)
• Range:
  • over water 5,396 nm (10,000 km) at 10 knots (19 km / h)
  • under water purely electric 80 nm (150 km) at 4 knots (7 km / h)
• Torpedo tubes: 5 (4 bow, 1 stern)
• Torpedoes: 11
• Board gun: 8.8 cm L / 45 with 220 rounds
• Crew: 42–46 men
• Diving depth: 130 m regular
  • 200 m extreme depth
  • 250 m calculated depth of destruction

Units
Ten submarines of this type were built between 1935 and 1937; all but two were sunk.

27 U · U 28 · U 29 · U 30 · U 31 · U 32 · U 33 · U 34 · U 35 · U 36

Type VII B

A disadvantage of the Type VII A was the short range and the lack of a rear torpedo room. For this reason, a total of 24 type VII B boats with a fuel capacity increased by 33 tons were built in the years 1936-1940, which increased the range to 6500 nm. In addition, they were a little faster and, thanks to a second rudder, more agile than the Type VII A. They were given a full-fledged stern torpedo room with space for a reserve torpedo. The VII B was also provided with four partitioned compartments on the upper deck, in which additional reserve torpedoes were stored, whereby a total of 14 torpedoes could be carried. In addition, thanks to its greater range and speed, it was suitable for high seas use in the Atlantic. After the keel was laid in 1938, the Type VII B paved the way for the most widespread submarine variant of all, the Type VII C.

Changes compared to type VII A:

• Displacement: total displacement 1,040 m³
  • over water 753 tons
  • under water 857 tons
• Length: 66.5 m in total, pressure body 48.8 m
• Width: 6.2 m in total, pressure body 4.7 m
• Draft: 4.74 m
• Height: 9.5 m
• Drive:
  • over water 3200 PS (2400 kW)
  • under water 750 PS (560 kW)
• Speed:
  • 17.9 knots above water
  • 8 knots under water
• Range:
  • over water 6,500 nm (12,000 km) at 12 knots
  • under water purely electric 90 nm (170 km) at 4 knots
• Torpedo tubes: bow 4, stern 1
• Reserve torpedoes: 7 internal, 2 external (external torpedoes had to be surfaced and brought into the torpedo room)
• Crew: 44–48 men
• Diving depth: 150 m (regular depth); 200 m (extreme depth)
• Immersion time: 30 seconds
• Guns:
  • 1 × 8.8 cm gun (anti-ship combat)
  • 1 × 2 cm Flak 30 (aircraft combat)

Units of
type VII B were built 24 boats.

U 45  ·  U 46  ·  U 47  ·  U 48  ·  U 49  ·  U 50  ·  U 51  ·  U 52  ·  U 53  ·  U 54  ·  U 55  ·  U 73
U 74  ·  U 75  ·  U 76  ·  U 83  ·  U 84  ·  85 U  ·  U 86  ·  U 87  ·  U 99  ·  U 100  ·  U 101  ·  U 102

Type VII C

Schematic representation of type VII C

U-Boot VII C - silhouette

The Type VII C was by far the most built submarine ever. It was also the most successful type of submarine in the entire history of naval warfare. By the end of the war, 577 units had been completed. It was longer than the VII B with the same drive power, which meant that the performance when submerged was slightly worse. In addition to the MAN engines, Krupp GW F46 engines were also installed. After the first commissioning of this variant in April 1940, these units formed the backbone of the submarine weapon in the Battle of the Atlantic.

Changes compared to type VII B:

• Displacement: total shape displacement 1,050 m³
  • above water 761 tons
  • under water 865 tons
• Length: 67.1 m in total, pressure body 50.5 m
• Width: 6.2 m in total, pressure hull 4.7 m
• Maximum speed when driving:
  • 17.6 knots above water
  • under water 7.6 knots
• Range:
  • over water 6,500 nm (12,000 km) at 12 knots
  • under water purely electrically 80 nm (150 km) at 4 knots
• Crew: 44–52 men
• Torpedoes carried: 14
• Immersion depth: 100 m (construction immersion depth)
  • 165 m (test diving depth)
  • 250 m (calculated depth of destruction; based on current knowledge, the depth of destruction was at least 280 m.)

Units
568 of the most frequently built submarine class were built in more than twelve different shipyards.

U 69 to U 72 U 77 to U 82 U 88 to U 98 U 132 to U 136 U 201 to U 212 U 221 to U 232 U 235 to U 291

U 301 to U 316 U 331 to U 394 U 396 to U 458 U 465 to U 473 U 475 to U 486 U 551 to U 683 U 701 to U 722

U 731 to U 768 U 771 to U 779 U 821 and U 822 U 825 and U 826 U 901 U 903 to U 905 U 907

U 921 to U 928 U 951 to U 994 U 1051 to U 1058 U 1101 and U 1102 U 1131 and U 1132 U 1161 and U 1162 U 1191 to U 1210

Type VII C / 41

U 995 , a version C / 41 boat, at its exhibition site in front of the Naval Memorial in Laboe in 2004

As the allied anti-submarine measures became stronger and stronger, the German naval command felt compelled to improve the Type VII C further. The second hull was reinforced in order to be able to withstand hits from small-caliber cannons better (because of the more and more armed freighters); likewise the pressure hull, which enabled greater diving depths and better protection against depth charges. In addition, the boats were built from lighter materials so that a lower overall weight was achieved, which slightly improved maneuverability and speed. A newly designed bow further improved maneuverability. Due to the constant improvement of the Allied radar and the danger posed by airplanes, improvements were necessary which enabled this type of boat to dive very quickly. This type was the second most frequently built German submarine. The first boat of this variant was delivered in August 1943.

Changes compared to Type VII C:

• Displacement: Total displacement 990 m³
  • over water 759 tons
  • under water 860 tons
• Immersion depth: 120 m (construction immersion depth)
  • 200 m (test diving depth)
  • 300 m (calculated destruction diving depth)
• Immersion time: 25 seconds
• Armament: 2 cm twin flak, heavy flak gun 3.7 cm
• Other: Snorkel instead of 8.8 cm deck gun
• 4 escape pods at the bow on the left

Units
91 units were built.

U 292 to U 300 U 317 to U 328 U 929 and U 930

U 995 and U 997 U 998 to U 1010 U 1013 to U 1025

U 1063 to U 1065 U 1103 to U 1110 U 1163 to U 1172

U 1271 to U 1279 U 1301 to U 1308

Interior views

• 

  E-engine room, behind it the diesel room

• 

  Pressure bulkhead, behind it the headquarters

• 

  Central, behind the bow room

• 

  Diesel room

• 

  Radio room

• 

  Control station of the electric machines

• 

  View from the headquarters into the tower

• 

  Bow room with the four torpedo tubes

• 

  Control room with depth control

• 

  Non-commissioned officers' bedroom

Type VII C / 42

This type is a new design from the experiences at the front up to 1942 and was noticeably larger than the previous types. By using armor material for the pressure hull, it should be able to reach the greatest diving depth of all submarines in World War II. This model no longer had a deck gun, which contributed to a higher underwater speed.

The contracts for this submarine class were terminated on September 30, 1943, and all boats already laid down were dismantled. Instead, the Type XXI submarines were built.

Changes compared to Type VII C:

• Displacement: Total displacement 1199 m³
  • over water 999 tons
  • under water 1099 tons
• Length: 68.7 meters
• Width: 6.7 meters
• Draft: 5.1 meters
• Max. Speed:
  • over water 18.6 knots (34.5 km / h)
  • under water 8.5 knots (15.7 km / h)
• Range:
  • over water 10,000 nm (18,500 km) at 12 knots
  • under water purely electrically 80 nm (150 km) at 4 knots
• Torpedoes: 16
• Immersion depth: 200 m (construction immersion depth)
  • 280 m (test immersion depth)
  • 400 m (calculated depth of destruction)
• Armament: 2 cm twin flak, heavy flak gun 3.7 cm
• other: snorkel instead of 8.8 cm deck gun

Type VII D

This type was designed as a mine-layer and had a center section that was about ten meters longer and contained five vertical shafts for receiving anchor mines. Due to the fact that all German submarine types were able to eject specially developed mines from the torpedo tubes and thus there was no increased need for mine-laying boats, only six boats were built.

Changes compared to Type VII C:

• Displacement: Total displacement 1285 m³
  • over water 965 tons
  • under water 1080 tons
• Length: 76.9 m in total, pressure hull 59.8 m
• Width: 6.38 m in total, pressure hull 4.7 m
• Draft: 5.01 m
• Height: 9.7 m
• Speed:
  • 16.7 knots above water
  • 7.3 knots under water
• Range:
  • over water 11,200 nm (20,700 km) at 10 knots
  • under water purely electric 69 nm (130 km) at 4 knots
• Torpedoes: 12
• Mines: 15
• Air defense: up to 1942 1 × 2 cm flak, later 2 × 2 cm flak + 1 × 3.7 cm flak
• Crew: 44 men

units

213 U  ·  U 214  ·  U 215  ·  U 216  ·  U 217  ·  U 218

Type VII F

This version was mainly built as a torpedo transporter. It was based on the Type VII D, whereby loading capacity for 25 torpedoes was created instead of the mine shafts. Since the takeover of torpedoes by another boat required the surfacing of both boats and this was very risky in the Atlantic , the boats were mainly used for transport between the bases, in particular to the base of the monsoon boats in Penang , Malaysia . Only four boats were built, only one of which survived the war.

Technical specifications:

• Displacement: total displacement 1345 m³
  • over water 1084 tons
  • under water 1181 tons,
• Length: 73.63 m in total, pressure hull 60.40 m
• Width: 7.3 m in total, pressure hull 4.7 m
• Draft: 4.91 m
• Height: 9.6 m
• Drive:
  • over water 2400 kW (3200 PS)
  • underwater 560 kW (750 PS)
• Speed:
  • 17.9 knots above water
  • under water 7.9 knots
• Range:
  • over water 14,700 nm (26,000 km) at 10 knots
  • under water purely electrically 75 nm (140 km) at 4 knots
• Torpedo tubes: bow 4, stern 1
• Torpedoes: 14 (25 as cargo)
• Crew: 46–52 men

units

U 1059  ·  U 1060  ·  U 1061  ·  U 1062

General remark

The specified data are usually to be regarded as maximum values. In particular, the actual range with electric motors was very much dependent on the condition and temperature of the batteries; these could vary widely. Information on the maximum immersion depth can also vary considerably due to repaired damage or differences in material quality. As a general rule, a new submarine made with good materials should go to extreme depth, but it is usually not more than 10 to 30 meters away. The further the war progressed after 1942, the worse the material quality became.

commitment

At the beginning of the war on September 1, 1939, the Navy had 19 Type VII boats. Ten of these boats were from the A series, which was used in the Spanish Civil War. Another 15 boats were under construction.

In the course of the war, the Type VII was used in all European seas, mainly in the Atlantic, but also in the North Sea, Baltic Sea, Arctic and the Mediterranean. The first sinking of a ship by a submarine in World War II was a type VII ( U 30 ) boat . The two submarines with the highest sunk ship space were also of type VII with U 48 and U 99 .

Of the 705 Type VII boats put into service, 437 were lost to combat operations. 165 boats were sunk themselves or handed over to the Allies at the end of the war. The loss of the remaining 100 or so boats was due to other causes, mainly the bombing of the ports or shipyards.

Significant sinkings by Type VII boats

date	Submarine	commander	Ship type	Ship name
09/17/1939	U 29	Otto Schuhart	Aircraft carrier	HMS Courageous
10/14/1939	U 47	Günther Prien	Battleship	HMS Royal Oak
11/14/1941	U 81	Friedrich Guggenberger	Aircraft carrier	HMS Ark Royal
11/25/1941	U 331	Hans Diedrich von Tiesenhausen	Battleship	HMS Barham
December 14, 1941	U 557	Ottokar Paulshen	cruiser	HMS Galatea
December 21, 1941	U 751	Gerhard Bigalk	Escort aircraft carrier	HMS Audacity
03/11/1942	U 565	Johann Jebsen	cruiser	HMS Naiad
08/11/1942	U 73	Helmut Rosenbaum	Aircraft carrier	HMS Eagle
02/01/1943	U 617	Albrecht Brandi	cruiser	HMS Welshman
02/18/1944	U 410	Horst-Arno Fenski	cruiser	HMS Penelope

Technical specifications

Conversions during the war

Since the Type VII was basically a further development of the German submarine designs of the First World War , its protection against air attacks with the only 20 mm automatic cannon is not very pronounced and had to be adapted to the changed requirements of the war. So came about:

1. Tower conversions:
   1. Tower 0:
      1. 2 cm Flak 30 or 38 in different mounts
      2. from 1942/43 with reinforced machine gun armament: 4 ×  MG 34 or MG 15 or 2 ×  MG 81 Z.
      3. Two additional Breda twin machine guns 13.2 mm on the Mediterranean boats.
   2. Tower I: only on U 553 (test boat): 1 × 2 cm Flak 30 and 2 ×  MG 151 Z.
   3. Tower II:
      1. 2 × 2 cm Flak 30 or 38 in different mounts.
      2. some boats in July 1943 received 1 × 2-cm Flak 30 or 38 and 1 × 2-cm Flak 38II in mount M43U.
   4. Tower III: only for a few boats in April / May 1943: 2 × 2 cm Flak 38.
   5. Tower IV:
      1. 2 × 2 cm Flak 30 or 2 ×  2 cm Flak 38 II in mount M43U and 1 ×  2 cm Flak Quad 38/42 in various designs as an interim solution.
      2. 2 × 2 cm Flak 38II in mount M43U 'and 1 ×  3.7 cm M42 U in various mounts
      3. U 1108 and U 1164 (trial): 2 × 2 cm Flak 38II in mount M43U 'and 1 × 3.7 cm M42 twin in double mount  .
   6. Special modifications were, for example, an anti-aircraft gun built into the leading edge of the turret (for example the 2 cm twin flak in the U 338 or 3.7 cm M42 in the U 673 ) or an anti-aircraft trap: the U 441 , for example, provided particularly heavy protection A 2 × 2 cm quadruplet (each in front of the tower and on the aft part of the tower) and a 3.7 cm anti-aircraft gun installed in the winter garden against air attacks . Since these attempts did not prove themselves in everyday life (including top-heaviness, splashing water, lake damage, extended diving times), they were mostly removed again.
2. Snorkeling: The snorkeling was the cruising permit from air raids under water in areas of high risk.
   1. Type I: air supply connection via flange on tower and rope drive.
   2. Type II: Supply air connection via flange on tower and pressurized oil system with crosshead drive.
   3. Type III: Supply air connection via the pivot of the snorkel mast and pressure oil system with crosshead drive.

In addition, there were further conversions to launch weather balloons or the lookout aircraft " Wagtail ", listening devices (for example GHG balcony or tower conversion for FuMO antennas) or installation of tower armor, inflatable boat containers and the expansion of the deck gun (from early 1943).

Dive duration

The air content of type VII-C was assumed to be 400 m³. The calculation was made with the release of 30 l / h CO ₂ and the consumption of the same amount of oxygen per crew member . With a 37-man crew, a CO ₂ content of 1.5% would be reached after 5 hours and 20 minutes . From this concentration onwards, an air purification system with alkaline cartridges should be used. With less than 17.5% remaining oxygen content, oxygen could be supplemented from ten pressure bottles , each with a volume of 50 liters and a pressure of 150  atmospheres . The oxygen supply and the alkali cartridges made it possible for a crew of 37 men to remain under water without interruption for 72 hours.

Test results

Noise emissions during diving trips

Command transmissions at a normal volume could by conventional means Horch still in two to three sm be obeyed distance. The relatively noisy systems and processes included the pumps , converters , contactors for the electrical control systems, blowing out with compressed air and, after the introduction of snorkeling, the diesel engines . Damaged devices, often by depth charges occurred -Ansprengungen could cause particularly strong and distinctive sounds that already far outside the ASDIC were perceived -Range.

The crawl speed range with e-machines extended to about 3 knots for all German submarine types before 1943  and was determined individually for each submarine. However, it was often objected that the electric machine noise was still located in the crawl speed range at speeds of under 120 / min, in which the propellers should no longer generate any noise. Systematic studies of structure-borne noise emissions only began during the course of the war. During a test run with a VII-C boat at a propeller speed of only 60 / min at a distance of 500 m, clearly audible e-machine noises were detected. From the end of 1943 these were reduced by changes in the e-machine slots. Against the structure-borne noise of the auxiliary machines, the attachment to vibration metal and springs was introduced.

At speeds of 90–120 / min and 150–210 / min, so-called propeller singing was detected in the types VII B and VII C in the 400–1200 Hz range. At 80 rpm (2.5 knots), the propeller singing range was measured to be 4.5 km. It could largely be stopped by a more precise production of the propeller blades. At high speeds, the propeller and electric machine noises dominated. At maximum speed the submarines were always quite loud.

Blast attempts

Blast tests with 125 kg loads at U 78 in August and December 1942 resulted in the following:

At a distance of 250 m, the scale of the gyro's daughter broke in the tower. At 180 m failure of the lamps , the diving alarm system and the rudder position indicator in the tower . If the rotation indicator Bb in the tower, machine voltmeter and ammeter 1 & 2, several lamps in the electric and diesel room, several fuses for the gyrocompass and the breakage of the water level glass for drinking water cell 2 failed, many lamps in the boat failed at 135 m . in particular the lighting of battery I. In addition, the diesel pressure reducer , gyroscope and daughter rose as well as the fuses for the auxiliary bilge and trim pump failed. The rudder angle indicator in the tower was bent, the pointer on the depth indicator 200 m fell off. The shock - accelerations were doing more than 1000 g  ≈ 9810 m / s, the shock paths mm only a maximum of 2.5. After these attempts, the boats were better insulated against shock. The previously often breaking and leaking battery boxes were given a soft rubber bag instead of the previous soft rubber lining, which leaked in over 50% of the broken boxes, which prevented the battery acid from leaking in 95% of all recorded box breaks .

art

• There are numerous artistic representations, among others by the marine painters Günther Todt and Viktor Gernhard .
• The boat U 96 is known from the novel Das Boot and the film of the same name Das Boot .
• The museum boat U 995 of type VII C / 41 is in Laboe .

See also

• List of German submarine classes
• List of German submarines: U 1 – U 250 • U 251 – U 500 • U 501 – U 750 • U 751 – U 1000 • U 1001 – U 1250 • U 1251 – U 1500
• List of bearers of the knight's cross of the iron cross of the submarine weapon

Web links

Commons : Submarine Class VII  - collection of pictures, videos and audio files

• The Type VII
• U-boat types at uboat.net (English)

Individual evidence

1. ↑ Fritz Köhn, Axel Niestle: From the original to the model: U-boat type VII C. A picture and plan documentation. Bernard & Graefe Verlag, Bonn 1994, ISBN 3-7637-6002-4 , p. 5.
2. ^ G. Helgason: U-boat Types Type VIIA. uboat.net, accessed December 22, 2008
3. ^ G. Helgason: U-boat Types Type VIIB. uboat.net, accessed December 22, 2008
4. ↑ M.Dv 381 U-Boating for submarines type VIIC-1940
5. ↑ Fritz Köhn, Axel Niestle: From the original to the model: U-boat type VII C. A picture and plan documentation. Bernard & Graefe Verlag, Bonn 1994, ISBN 3-7637-6002-4 , p. 6.
6. ^ G. Helgason: U-boat Types Type VIIC. uboat.net, accessed December 22, 2008
7. ↑ Erminio Bagnasco: Submarines in World War II. Technology class types. ISBN 3-613-01252-9 , p. 69.
8. ^ G. Helgason: U-boat Types Type VIIC / 41. uboat.net, accessed December 22, 2008
9. ↑ Fritz Köhl, Axel Niestle: From the original to the model: U-boat type VII C. A picture and plan documentation. Bernard & Graefe Verlag, Bonn 1994, ISBN 3-7637-6002-4 , p. 8.
   Bodo Herzog : German U-Boats 1906–1966. Karl Müller Verlag, Erlangen 1999, ISBN 3-86070-036-7 , p. 197.
10. ↑ G. Helgason: U-boat Types Type VIIC / 42. uboat.net, accessed December 22, 2008
11. ↑ Erminio Bagnasco: Submarines in World War II. Technology class types. ISBN 3-613-01252-9 , p. 70.
12. ↑ Erminio Bagnasco: Submarines in World War II. Technology class types. ISBN 3-613-01252-9 , p. 71.
13. ↑ for the entire section: Fritz Köhl, Axel Niestle: From the original to the model: U-boat type VII C. A picture and plan documentation. Bernard & Graefe Verlag, Bonn 1994, ISBN 3-7637-6002-4 , pp. 19-36. The complete list of conversions goes over two pages
14. ↑ M.Dv 381 U-Boatskunde U boats type VIIC 1940
15. ↑ Eberhard Rössler : History of the German submarine building, Volume 1 . Licensed edition for Bechtermünz Verlag in Weltbild Verlag GmbH, Augsburg 1996, ISBN 3-86047-153-8 (Chapter 6.65. The stability of the German submarines and the lethality of the allied anti-submarine weapons).