U-Boat Type 7 class (VII), most numerous German submarines of World War II with 705 boats.
History, development, service, specifications, statistics, pictures and 3D model.
Type 7C, 7A, 7B, 7D (total of 705 U-boats Type VII)
Table of Contents
Under the terms of the Treaty of Versailles Germany was not allowed to retain or build any submarines so that at the outbreak of war in 1939 the German U-boat fleet was comparatively modern, all the vessels having been built since 1935. Between 1919 and 1934 German submarine technicians had not been idle, and among those submarines built in various European shipyards to German design and with German technical assistance were Gür built in 1932 for the Turkish navy, and Vesikko built in 1933 for Finland.
Gür was 72.4 m (237 ft 6 in) long and displaced 750 tons (surfaced) and 960 tons (submerged), and was armed with six torpedo tubes (four bow and two stern) and one 4-in (102-mm) gun. Vesikko was a smaller boat of only 250 tons (surfaced) and 300 tons (submerged); it was 40.8 m (134 ft) long, and armed with three bow 53-cm (21-in) torpedo tubes and a small gun.
Thus, Gür provided a prototype for an ocean-going submarine, while Vesikko was the forerunner of the coastal submarines.
In order to get the building program under way as rapidly as possible to fulfil the need to have submarines at sea and to train future crews, it was the coastal submarines of Type II, as they were to be known, that were the first to be laid down. The first such boat for the German navy, called U-1, was launched in Kiel in June 1935, the remainder following shortly afterwards. The class II B and II C were similar, but were larger and carried additional fuel to increase their range. II D boats were introduced in 1940; they were still larger; and were fitted with saddle tanks to increase their range further. Although used for operations early in the war these boats were soon relegated to training duties, an essential part of the enormous expansion program that the U-Boat arm was to undertake.
Meanwhile, the Type I, of which only two boats were built, gave the German navy a capability of operations in the Atlantic. Basically the same design and performance as Gür, these two boats in turn were to become the prototype, with the UB48 Class of 1917, of a new series of ocean-going submarines, the Type VII U Boat. This type, with its several variants, was undoubtedly the mainstay of the German submarine fleet throughout the war. The variants retained many structural characteristics of the original Type VII but were designed either for better performance or for more specialized roles.
The first U-boat VII A was U-27, launched in 1936, designed for operations in the Atlantic. It had good sea keeping qualities and easy handling both on the surface and submerged, and carried the best possible torpedo armament that could be fitted into a submarine of less than 65 m (213 ft) in length and only 626 tons surfaced displacement. Inevitably this was achieved at the expense of other factors, and habitability was spartan, to say the least. The U boats VII As are distinguished by their single external torpedo tube aft. U 30, a boat of this type, was responsible for sinking the liner Athenia early in the war.
U-45, the first U-boat VII B, was launched in April 1938. The type had increased size and displacement to accommodate higher-performance engines and more fuel. The stern torpedo tube was made internal with the hull. The U-47 commanded by Korvetten-Kapitän Günther Prien entered Scapa Flow in 1939 and sank Royal Oak, and later was to sink many thousands of tons of Allied shipping in the Atlantic.
The 7C U-boats (VII C), introduced in 1940, had a further increase in displacement and fuel capacity, more torpedo reloads, and a better AA armament. Contracts were placed for 688 submarines of this type, though later some of these were cancelled and others were destroyed by enemy action during construction.
The VII C-41 class differed only in that it had a stronger hull to give a greater diving depth. Eight submarines of this type were to have been completed for the Italian navy, but they were taken into commission by the Germans themselves following the Italian surrender. U 573 was interned in Spain at Cartagena after being badly damaged by depth charges dropped from an RAF aircraft in 1942. The following year she was sold to Spain and renumbered G7. U 570 surrendered after being damaged by an RAF aircraft south of Iceland, and later was commissioned as HMS Graph.
Orders for a second variant, the U-boats 7 C-42, were cancelled to allow production to concentrate on newer types. Had it entered service it would have had increased range and an even greater diving depth.
A mine laying variant, the U-boats VII D, was introduced in 1942. The six boats of this type had a 9.8-m (32 ft 2-in) section added into the hull aft of the conning tower to take five freeflooding mine chutes carrying a total of 15 moored mines similar to those carried by surface mine layers.
In the VII F this extra section was adapted to carry 25 torpedoes to replenish other submarines already on patrol. Four boats of this type were built, and they carried additional fuel to increase their range. In addition to the replenishment torpedoes for other boats they had their own establishment of torpedoes to carry out their own operations.
A total of 705 boats of all variants had entered service by the time of the surrender in 1945, and of these, 437 were lost in action. The U977 (VIIC) left Norway rather than surrender, and after a continuous submerged passage of 66 days reached Argentina on August 17, 1945, where her crew were interned.
The U-boats XIV were tanker U-Boats derived from the VIIC class. They were used to supplying fuel to ether submarines to increase their time on patrol, and for this purpose they carried an additional 203 tons of fuel. They had no torpedo tubes of their own though they carried four torpedoes for transfer to other boats.
Users: Germany, Spain, Japan.
Museum U-boat U-995 (VIIC)
Launched: July 22, 1943 (Hamburg); commissioned September 16, 1943
History: On VE-day (May 8, 1945) surrendered to Great Britain. In 1952 handed over to Norwegian navy. In use as training submarine until 1962. Given back to Germany in 1965 and rebuild to the condition of May 1945. Since 1977 as museum u-boat in exhibition at Laboe (Germany).
Pictures from interior and outer of U-995:
Animated 3D model of U-boat VIIB
Specifications for German U-boats Type VII
|Displacement (surfaced / submerged)||626/745 tons||753/857 tons||769/871 tons||769/871 tons|
|Length||213 ft (64.9 m)||219.5 ft (66.9 m)||221.5 ft (67.5 m)||221.5 ft (67.5 m)|
|Beam||19.4 ft( 5.9 m)||20.3 ft (6.2 m)||20.3 ft (6.2 m)||20.3 ft (6.2 m)|
|Draught||14.4 ft (4.4 m)||15.4 ft (4.7 m)||15.4 ft (4.7 m)||15.4 ft (4.7 m)|
|Engines||two diesel, one electric motor with 2 shafts|
|Power||2800 hp surfaced, 750 hp submerged|
|Fuel||67 tons||108 tons||114 tons||114 tons|
|Speed (surfaced / submerged)||17/8 kn||18/8 kn||17.75/7.5 kn||17.5/7.5 kn|
|Range||4,300 nm at 12 kn||6,500 nm at 12 kn||6,500 nm at 12 kn (8,850 nm at 10 kn)|
|Diving depth (max)||?||490 ft||590 ft|
|Quick diving||?||30 sec||25-30 sec|
|Torpedo tubes||4 bow 21-in (53.3 cm) torpedo tubes, 1 stern 21-in torpedo tube|
|Secondary Armament||1 x 3.5-in (8.8 cm) gun||-||-||-|
|Anti-aircraft||1 x 2 cm (0.79-in)||1 x 3.7 cm (1.46-in); 2 x 2 cm (0.79-in)||1 x 3.7 cm (1.46-in); 2 x 2 cm (0.79-in)||1 x 3.7 cm (1.46-in); up to 3 x 2 cm (0.79-in)|
|sub VIIB||U45-55; 73-76; 83-87; 99-102|
|sub VIIC||U69-72; 77-82; 88-98; 132-136; 201-212; 221-232; 235-458; 465-486; 551-683; 701-779; 821-836; 901-08; 921-930; 951-1058; 1063-1065|
|sub VIIC-41||U 1101-1220; 1271-1279; 1301-1308|
|Launching (all)||June 1936 (U-27) - November 1944 (U-1308). VIIC from 1940.|
|Fate||437 sunk for different reasons, 165 scuttled at VE day, 103 surrendered|
Development of the U-boat arm 1942-1945
German U-boat arm:
|month||commission||in service||losses||losses total|
References and literature
Fighting Ships of the World (Antony Preston)
Kriegsschiffe von 1900 bis heute – Technik und Einsatz (Buch und Zeit Verlagsgesellschaft)
The Illustrated Directory of Warships from 1860 to the present day (David Miller)
Kriegsschiffe 1939-45 (Heyne-Bildpaperback)
Flotten des 2. Weltkrieges (Antony Preston)
Die Schlacht im Atlantik (Andrew Kershaw)
U-Boote seit 1919 (Antony Preston, John Batchelor)
U-Boote im Duell (Harald Bendert)
Das Deutsche Reich und der Zweite Weltkrieg (10 Bände, Zentrum für Militärgeschichte)
World War II – A Statistical Survey (John Ellis)
Chronology of World War II (Christopher Argyle)
Seemacht – eine Seekriegsgeschichte von der Antike bis zur Gegenwart (Elmar B. Potter, Admiral Chester W.Nimitz)