Type VIIC U-boat

Type VIIC U-boat was the main German submarine variant of the Second World War, built in about 568 boats between 1940 and 1945, the most numerous submarine class in history. The VIIC was the production version of the Type VII family, longer and heavier than the earlier VIIA and VIIB, with more fuel, more torpedoes, and a slightly larger hull that let it carry the active sonar, the snorkel, and the heavier anti-aircraft armament that the war demanded. The VIIC was the boat of the wolfpacks, the boat of the Happy Time and of Black May, and the boat of Das Boot, the film that showed the world what life was like aboard a U-boat. It sank more Allied shipping than any other submarine variant, and it suffered the heaviest losses: about 80 per cent of the VIIC boats were lost, and about 25,000 German submariners died in them. The VIIC was not a new design, but a refinement of the Type VII, and its story is the story of the U-boat war at its height and at its defeat.

1. Key Facts

Class/Type	Type VIIC U-boat (variant of the Type VII family)
Launched	First boat, U-69, launched 1940
Commissioned	1940-1945
Displacement	About 769 tons surfaced; about 871 tons submerged
Length	67.1 metres
Speed	About 17.7 knots surfaced; about 7.6 knots submerged
Complement	44-52 officers and men
Armament	5 torpedo tubes (4 bow, 1 stern); 14 torpedoes; 1 x 88 mm deck gun; 1 x 20 mm and later 1 x 37 mm anti-aircraft guns
Aircraft	None
Fate	About 568 built; most lost; U-995 preserved at Laboe

2. Development

From VIIB to VIIC

The Type VIIC was developed from the Type VIIB, which had been built in 24 boats in 1938 and 1939. The VIIB was longer than the VIIA, with more fuel and a longer range, but the navy wanted still more fuel, more torpedoes, and space for new equipment. The VIIC added about 0.6 metres to the length, increased the fuel capacity to about 114 tons, and added a saddle tank that let the boat carry more fuel and more torpedoes. The first VIIC, U-69, was laid down in 1939 and commissioned in November 1940, and production continued through the war, with boats built at shipyards in Kiel, Hamburg, Bremen, Danzig, and other ports. The VIIC was built in larger numbers than any other submarine, because it was the boat the German navy needed for the Atlantic war, and because it could be built quickly, in about six months, by yards that had learned the design.

Production and the U-boat Programme

The VIIC was built under the U-boat programme that Admiral Karl Donitz had planned before the war, which called for 300 U-boats, and which was expanded after the outbreak of war to more than 1,000 boats. The VIIC was the main production type, and about 568 boats were completed, compared with 10 VIIA, 24 VIIB, 91 VIIC/41, 6 VIID, and 4 VIIF boats in the same family. The boats were built in series, with improvements added as the war went on: the snorkel, the radar detector, the heavier anti-aircraft armament, and the active sonar. The production was a major industrial effort, involving thousands of workers and hundreds of suppliers, and it was disrupted by Allied bombing, which damaged shipyards and delayed deliveries. Despite the bombing, the VIIC was built in large numbers, and it was the boat that carried the U-boat war to its peak in 1942 and to its defeat in 1943.

3. Design

The VIIC Hull

The VIIC hull was 67.1 metres long, 6.2 metres wide, and about 4.7 metres in draught, with a surfaced displacement of about 769 tons and a submerged displacement of about 871 tons. The pressure hull was divided into six compartments, as in the earlier Type VII boats, but the VIIC had a slightly larger hull, with more space for fuel, torpedoes, and equipment. The boat was a single-hulled design, with saddle tanks on the sides that carried fuel and ballast, and with a conning tower that carried the bridge, periscopes, and anti-aircraft guns. The boat’s design was a compromise: it was small enough to be built quickly, large enough to operate in the Atlantic, and fast enough to keep up with a convoy, but it was cramped, with the crew living in bunks that were shared in shifts, and with little space for stores or fresh water. The VIIC’s hull was the standard for the U-boat war, and it was the hull that the film Das Boot made famous.

The Snorkel and Later Fittings

The VIIC was fitted with a snorkel from 1944 onwards, a breathing tube that let the diesels run while the boat was submerged at periscope depth, charging its batteries without surfacing. The snorkel was a major improvement, because it let the boat stay submerged for longer, and it reduced the risk of being found by aircraft, although it was not a perfect solution: the snorkel could be detected by radar, and it limited the boat’s speed and depth. The VIIC was also fitted with a radar detector, the Metox, and later with a radar set, the FuMO 29, and with a heavier anti-aircraft armament, including a quadruple 20 mm mount on some boats. The fittings were added as the war went on, in response to Allied countermeasures, and they made the VIIC heavier and slower, but they also made it more survivable. The VIIC/41, a later variant with a stronger pressure hull, was built in 91 boats, and it could dive deeper than the VIIC, to about 250 metres.

4. Technical Specifications

Dimensions and Performance

The Type VIIC measured 67.1 metres in length, 6.2 metres in beam, and 4.7 metres in draught. Her surfaced displacement was about 769 tons, and her submerged displacement was about 871 tons. Her surface speed was about 17.7 knots, and her submerged speed was about 7.6 knots, although she could only maintain that speed for a short time before her batteries were exhausted. Her range was about 8,500 nautical miles at 10 knots on the surface, and about 80 nautical miles at 4 knots submerged. Her test depth was about 220 metres, although boats were often driven deeper in emergencies, and the VIIC/41, with its stronger hull, could dive to about 250 metres. Her complement was 44 to 52 officers and men, including the commander, officers, petty officers, and ratings. The boat carried 14 torpedoes, or 26 mines in place of torpedoes, and its fuel capacity was about 114 tons. The figures vary between sources because the boats were modified during production.

Machinery and Sensors

The VIIC was powered on the surface by two diesel engines, producing about 3,200 horsepower, and submerged by two electric motors, producing about 750 horsepower. Her two shafts drove two propellers, and her batteries, which powered the electric motors, could be charged by the diesels on the surface or by the snorkel at periscope depth. Her sensors included the Gruppenhorchgerat, a group listening device, for passive sonar, and an active sonar set for ranging. Her periscopes were the attack periscope, for torpedo aiming, and the observation periscope, for general observation. Her radio equipment included a transmitter and receiver for long-range communication, and a radar detector, which warned of Allied radar. Her torpedo fire control was manual, with the commander calculating the firing solution from the periscope, and her torpedoes were the standard G7a steam and G7e electric types, with a range of about 5,000 metres at high speed.

5. Armament

Torpedoes in Detail

The VIIC carried five torpedo tubes, four in the bow and one in the stern, and 14 torpedoes. The torpedoes were carried in the bow and stern torpedo rooms, and in external containers under the deck, and they were loaded by hand, a slow and dangerous job in heavy weather. The boat could fire a spread of four torpedoes from the bow, reload in about 20 minutes, and fire again, and it could fire a single torpedo from the stern at a pursuing escort. The torpedoes were the G7a, a steam torpedo with a range of about 12,500 metres at 30 knots, and the G7e, an electric torpedo with a range of about 5,000 metres at 30 knots, which left no wake and was harder to detect. The boat also carried the FAT and LUT torpedoes, which ran in a pattern after missing their target, and the acoustic torpedo, the Zaunkonig, which homed on the noise of a ship’s propellers, although the acoustic torpedo was unreliable and was used only from 1943 onwards.

Deck Gun and Anti-Aircraft Guns

The VIIC carried an 88 mm deck gun, mounted forward of the conning tower, which was used to sink small ships and to finish off damaged ships, saving torpedoes for larger targets. The deck gun was effective in the early war, when Allied ships were unarmed, but by 1942 most merchant ships carried guns, and the deck gun became too dangerous to use. The gun was removed from many VIIC boats in 1943 and 1944, to save weight and to reduce drag, and the boats relied on torpedoes alone. For air defence, the VIIC carried a 20 mm anti-aircraft gun, and later a 37 mm gun and a quadruple 20 mm mount, on the conning tower platform. The guns were a last resort, because a submarine that fought an aircraft on the surface was likely to be sunk, and the standard tactic was to dive. The anti-aircraft guns were more useful against single aircraft, and they were sometimes used to shoot down patrol aircraft, but by 1944 the boats relied on the snorkel and on diving to escape.

6. Service History

The Wolfpacks of 1942

The VIIC was the boat of the wolfpacks, the groups of 10 to 20 boats that were directed by radio to a convoy and attacked together, at night, on the surface. The wolfpack tactic reached its peak in 1942, when the VIIC boats sank more than 6 million tons of Allied shipping, the highest total of the war. The boats operated from bases in France, at Brest, Lorient, and Saint-Nazaire, which gave them direct access to the Atlantic, and they were supported by supply boats, the Milchkuhe, which refuelled and rearmed them at sea. The VIIC boats that sailed in 1942 were commanded by experienced officers, many of whom had been in the U-boat force since before the war, and they were crewed by men who had trained for years. The success of 1942 was due to the VIIC’s numbers, its crews’ experience, and the unreadiness of the Allied defences, which had not yet introduced escort carriers and long-range aircraft in sufficient numbers.

Black May and the Defeat

In May 1943, known as Black May, the Allies sank 43 U-boats in a single month, most of them VIIC boats, and Admiral Donitz withdrew his boats from the Atlantic. The defeat was due to Allied countermeasures: radar, which could find a U-boat on the surface at night; the Leigh Light, which let aircraft attack at night; escort carriers, which provided air cover for convoys; and the Huff-Duff direction finder, which located U-boats by their radio transmissions. The VIIC, which had been designed for a war in which it could operate on the surface, was vulnerable to aircraft, and its slow submerged speed made it an easy victim for escorts. After Black May, the VIIC boats that sailed were often sunk before they reached their patrol areas, and the U-boat war became a losing battle. The VIIC continued to serve to the end of the war, but it never recovered its advantage, and it was replaced by the Type XXI, which could stay submerged and outrun escorts.

7. Notable Actions

U-96 and Das Boot

U-96, a Type VIIC under Heinrich Lehmann-Willenbrock, is the most famous VIIC because her patrol was the basis for the novel and film Das Boot, by Lothar-Gunther Buchheim, who sailed aboard U-96 as a war correspondent in 1941. U-96 sank 27 ships totalling about 180,000 tons in 11 patrols, and she survived the war, being scuttled in March 1945. Buchheim’s novel, published in 1973, and the film, released in 1981, showed the life of a U-boat crew in the Atlantic: the boredom, the fear, the cold, and the camaraderie, and they made the VIIC famous to a generation that had not lived through the war. The film was shot in a replica of a VIIC, and it is regarded as one of the most accurate portrayals of submarine warfare ever made. U-96’s story is the story of the VIIC at its height, when the boats were still winning the war.

U-995 and the Last Boat

U-995, a Type VIIC/41, is the only surviving VIIC, preserved as a museum ship at Laboe, Germany. U-995 was commissioned in September 1943, served in the Arctic, off Norway, and was surrendered to Britain in May 1945. She was transferred to Norway, where she served as the submarine Kaura until 1965, before being returned to Germany and preserved at Laboe in 1971. U-995 is the only VIIC on display, and she is visited by hundreds of thousands of people each year. The boat’s preservation is a tribute to the VIIC crews, and to the 30,000 German submariners who died, most of them in VIIC boats. U-995’s interior, with its bunks, torpedo tubes, and control room, shows the cramped conditions in which the crews lived, and it is the best-preserved example of the most numerous submarine class in history.

8. Fate

Losses of the VIIC

Most VIIC boats were lost in action. Of the about 568 boats built, about 450 were sunk, and about 25,000 German submariners died in them, a casualty rate of about 80 per cent. The losses were heaviest in 1943 and 1944, when Allied aircraft and escort groups made the Atlantic impassable for U-boats. The VIIC’s size and slow submerged speed made it an easy target, and its long patrols exposed it to danger for longer. Some boats were lost to accidents, mines, and friendly fire, but most were sunk by aircraft, destroyers, and escort carriers. The last VIIC patrols, in 1945, were to the British coast and the Atlantic, and the boats that sailed often did not return. The war ended with the VIIC obsolete, overtaken by the Type XXI, which could stay submerged and outrun escorts, and by the Allied countermeasures that had defeated it.

Survivors and Preservation

Only one VIIC survives: U-995, a VIIC/41, preserved at Laboe, Germany. The other surviving boats were divided among the Allies after the war and scrapped or used for trials. U-995’s preservation was due to her service in Norway, where she was maintained as an operational submarine until 1965, and to the efforts of the German Naval Association, which raised her as a memorial. The boat is now a museum, and she is the only place where visitors can see the interior of a VIIC, the boat that defined the U-boat war. The VIIC’s legacy is preserved in U-995, in the film Das Boot, and in the records of the U-boat war, which show the VIIC as the most numerous and the most successful submarine class in history, and as the boat that suffered the heaviest losses.

9. Legacy

The Most Numerous Submarine

The VIIC was the most numerous submarine class in history, with about 568 boats built, and it remains the standard by which other submarine classes are measured. Its design, which balanced size, speed, and armament, set the pattern for medium submarines, and its wolfpack tactics, which used radio direction to concentrate boats on a convoy, were a new way of waging war at sea. The VIIC also showed the limits of the submarine: it was a surface ship that could submerge, not a true submarine, and it depended on the surface for speed and for charging its batteries. The Allied countermeasures, radar, sonar, escort carriers, and long-range aircraft, exploited that dependence, and by 1943 the VIIC could not operate in the Atlantic without being found and sunk. The lesson was learned by the German navy, which replaced the VIIC with the Type XXI, and by the post-war navies, which built true submarines that could operate submerged for weeks.

Memory and Das Boot

The VIIC is remembered in the film Das Boot, which made the boat famous, and in the museum ship U-995, which is the only surviving VIIC. The boat is also remembered in the memorials to the U-boat war, in Germany and in Britain, which commemorate the submariners and the merchant seamen who died in the Atlantic. The VIIC’s crews, who sailed in the most numerous submarine class in history, suffered the highest losses of any service in the war, and their story is told in the memorials and in the film. For historians, the VIIC stands as an example of a weapon that was superbly suited to the war it was designed for, and that became obsolete when the enemy learned to counter it, a pattern that has repeated in naval warfare ever since. The VIIC’s story is the story of the U-boat war itself.

10. Frequently Asked Questions

What was the Type VIIC U-boat?

The Type VIIC was the main German submarine variant of the Second World War, built in about 568 boats between 1940 and 1945. It was the most numerous submarine class in history, and it formed the backbone of the wolfpacks in the Atlantic. The VIIC was the production version of the Type VII family, longer and heavier than the earlier VIIA and VIIB, with more fuel and more torpedoes. Its slightly larger hull let it carry the active sonar, the snorkel and the heavier anti-aircraft armament that the war demanded.

How many Type VIIC U-boats were built?

About 568 Type VIIC boats were built between 1940 and 1945, the most numerous submarine class in history. The Type VII family as a whole, including the VIIA, VIIB, VIIC, VIIC/41, VIID and VIIF, totalled about 703 boats. The first VIIC boat, U-69, was launched in 1940, and the VIIC was the boat of the wolfpacks, the Happy Time and Black May. It sank more Allied shipping than any other submarine variant, and it suffered the heaviest losses, with about 80 per cent of the VIIC boats lost.

How did the VIIC differ from the VIIB?

The VIIC was longer and heavier than the VIIB, with more fuel, more torpedoes, and space for new equipment such as the snorkel. The VIIB carried 14 torpedoes, as did the VIIC, but the VIIC had a longer range, because it carried more fuel in a slightly larger hull. The VIIC was the production version of the Type VII family, and its larger hull let it carry active sonar and heavier anti-aircraft armament. The VIIC was built in about 568 boats between 1940 and 1945, the most numerous submarine class in history, and the boat of the wolfpacks.

What was Das Boot?

Das Boot was a novel by Lothar-Gunther Buchheim, published in 1973, and a film released in 1981, based on a patrol aboard the Type VIIC U-96 in 1941. It is regarded as one of the most accurate portrayals of submarine warfare, and it showed the world what life was like aboard a U-boat. The VIIC was the boat of Das Boot, the boat of the wolfpacks, the Happy Time and Black May, and the main German submarine variant of the war. About 568 VIIC boats were built between 1940 and 1945, they sank more Allied shipping than any other variant, and about 80 per cent were lost.

Where can I see a Type VIIC today?

U-995, a Type VIIC/41, is preserved as a museum ship at Laboe, Germany, and she is the only surviving Type VIIC. She is the only place where visitors can see the interior of the boat, and the only surviving boat of the most numerous submarine class in history. About 568 VIIC boats were built between 1940 and 1945, and most were lost, with about 450 sunk and about 25,000 German submariners dead in them. The VIIC was the main German submarine variant of the war, the boat of the wolfpacks, and U-995 at Laboe is its last survivor.

How many VIIC boats were lost?

About 450 of the about 568 VIIC boats were sunk, and about 25,000 German submariners died in them, a casualty rate of about 80 per cent. That was the highest casualty rate of any service in the war, and the VIIC suffered the heaviest losses of any submarine variant. The VIIC was the boat of the wolfpacks, the Happy Time and Black May, and it sank more Allied shipping than any other submarine variant. About 568 VIIC boats were built between 1940 and 1945, and only one, U-995, survives today, preserved as a museum ship at Laboe, Germany.

11. Sources

1. Wikipedia, “German Type VII submarine” — VIIC production, specifications, and service.
2. Clay Blair, “Hitler’s U-Boat War: The Hunters, 1939-1942” and “The Hunted, 1942-1945” (Random House, 1996-1998) — the U-boat war and the wolfpacks.
3. Erich Groner, “German Warships 1815-1945, Vol. 2: U-boats and Mine Warfare Vessels” (Conway, 1991) — specifications and production data.
4. Uboat.net, “Type VIIC” — boat lists, patrols, and losses.
5. Lothar-Gunther Buchheim, “Das Boot” (Piper, 1973) — life aboard U-96, a Type VIIC.
6. German Naval Association, Laboe, “U-995” — the preservation of U-995.