Type VII submarine
In 1935, the Reichsmarine placed its first order for a medium attack U-boat. This decision came before Adolf Hitler openly renounced the Treaty of Versailles in March that year. Germany had circumvented the treaty since World War I by establishing NV Ingenieurskantoor voor Scheepsbouw Den Haag, a Dutch dummy company. The firm designed submarines based on the Type UB III from World War I and built three units for Finland called the Vetehinen class in 1931. Parts were produced for German use, but assembly was held back to avoid offending Great Britain. The Anglo-German Naval Agreement later officialized this breach, allowing Germany to limit total tonnage to 45% of British submarine tonnage. Karl Dönitz became supreme commander of the U-boat division in 1935 and advocated for these specific vessels. Erich Raeder, head of the German Navy, imposed a more balanced fleet including minelayers and coastal subs instead. At the start of the war on the 3rd of September 1939, only eighteen Type VII boats were in service.
The first subtype, Type VIIA, measured 67 meters overall with a beam of 6.20 meters. Ten boats were built between 1935 and 1937 at Deschimag AG Weser in Bremen and Friedrich Krupp Germaniawerft in Kiel. The boat used two MAN diesel engines producing 3,200 horsepower for surface travel. A single-hull design meant the outer hull served as the pressure hull, reducing oil leak risks during depth charge attacks. Saddle tanks contained diving and trimming tanks while fuel sat inside the pressure hull. The main ballast tank was also internal, resulting in a thirty-second dive time. Type VIIB extended the hull by four meters to increase range. It added saddle tanks holding 48 cubic meters of fuel, sacrificing the safety of internal storage. Two engine types appeared: the MAN M6V40/46 and the near-identical Germaniawerft F46. The Type VIIC added a full frame section of 1.5 meters to house sonar equipment. This modification reduced speed marginally but allowed navigation through minefields. By 1940, U-boats operated from French bases where mines were less common, so sonar installation ceased.
All Type VII U-boats carried four bow tubes and one stern tube with five torpedoes loaded initially. Forward compartments held four extra rounds below deck while cradles on the inner deck stored two more. An external watertight container held two spare torpedoes above the forward compartment and behind the conning tower. Reloads required opening hatches that prevented diving until completed. Early versions mounted an 8.8 cm SK C/35 quick-firing deck gun intended for finishing off sinking ships. Torpedoes could be economized by using the gun instead. Surface operations left vessels vulnerable since a single hit on the pressure hull rendered them unable to dive. From late 1942 onward, crews removed the deck gun to save weight for anti-aircraft defenses. One 2 cm C/30 anti-aircraft gun sat on a platform at the rear of the conning tower. Mid-1942 upgrades enlarged this platform and added a second lower tier. The 2 cm C/38 replaced the older model in mid-January 1943. Twin mountings became standard by October 1943. A heavier 3.7 cm Flak 43 naval version arrived in November 1943 to replace quadruple 2 cm mounts. Snorkel technology eventually allowed U-boats to avoid aircraft by cruising submerged.
The Type VII program began slowly after the Anglo-German Naval Agreement in 1935. By war's end, 709 boats had been commissioned across multiple shipyards. An ambitious Enlarged U-boat Construction Program set yearly targets of 275 units including 207 Type VIIs. Shortages in skilled labor and raw materials revised these goals in June 1940. The Restricted U-boat Construction Program foresaw 292 total boats by the 1st of January 1942, with 191 being Type VIIs. Massive construction halted abruptly in September 1943 when the class became obsolete. Orders for new Elektroboote took priority over existing designs. Only the small Flender Werke yard continued building until January 1944. Eighty-eight Type VIIC/41s were commissioned before production stopped completely. Most remaining boats were scuttled by crews during Operation Regenbogen or later by British forces under Operation Deadlight. A single survivor remains on display at the Laboe Naval Memorial in Schleswig-Holstein.
Karl Dönitz advocated Wolfpack tactics using these medium attack U-boats against convoys. At the start of World War II, only eighteen of fifty-six commissioned U-boats were Type VIIs. Two early successes included sinking the aircraft carrier HMS Courageous and battleship HMS Royal Oak. Four Type VII boats distinguished themselves during the First Happy Time after France fell. U-96 became the top-scoring vessel with three successive commanders earning the Knight's Cross of the Iron Cross. Attacks stalled after March 1941 losses shifted focus deeper into the Atlantic. Operations drained resources to the Mediterranean Sea where sixty-two boats transferred between September 1941 and April 1944. Hitler insisted on sending units to help Italy while others guarded Norway against invasion. Between December 1941 and August 1942, Type VIIs mounted one hundred four patrols off Newfoundland and Labrador. They sank two hundred twenty-five ships totaling over one million tons. Convoy battles peaked in March 1943 before heavy losses forced withdrawal from the North Atlantic on May 24. By the 1st of April 1944, all Type VIIs remained in port anticipating Operation Overlord.
Common questions
What was the Type VII submarine class and when did Germany order its first units?
The Type VII submarine was a German medium attack U-boat class ordered by the Reichsmarine in 1935. This decision occurred before Adolf Hitler openly renounced the Treaty of Versailles in March that year.
How many Type VII boats were built and what shipyards produced them between 1935 and 1944?
A total of 709 Type VII boats were commissioned across multiple shipyards during World War II. Production began at Deschimag AG Weser in Bremen and Friedrich Krupp Germaniawerft in Kiel, with construction halting abruptly in September 1943 and ending completely by January 1944.
When did the Type VII submarine program begin and how many vessels were operational at the start of World War II on the 3rd of September 1939?
The Type VII program officially began after the Anglo-German Naval Agreement in 1935. At the start of the war on the 3rd of September 1939, only eighteen Type VII boats were in service out of fifty-six commissioned U-boats.
What specific modifications distinguished the Type VIIC subtype from earlier versions like the Type VIIB?
The Type VIIC added a full frame section of 1.5 meters to house sonar equipment which allowed navigation through minefields. This modification reduced speed marginally but enabled operations until 1940 when U-boats operated from French bases where mines were less common.
How did the Type VII submarine class perform against Allied convoys between December 1941 and August 1942 off Newfoundland and Labrador?
Between December 1941 and August 1942, Type VII submarines mounted one hundred four patrols off Newfoundland and Labrador. These operations sank two hundred twenty-five ships totaling over one million tons before convoy battles peaked in March 1943.