G7e torpedo

G7e torpedo
German G7e torpedo in the middle
Type	Heavyweight homing torpedo
Place of origin	Nazi Germany
Service history
Used by	Kriegsmarine
Wars	World War II
Production history
Variants	G7e/T2 G7e/T3 G7e/T4 Falke
Specifications
Length	7.16 metres (23.5 ft)
Diameter	533 millimetres (21.0 in)
Engine	Electric Lead-acid batteries
Launch platform	Submarines

The G7e or more appropriately the G7e/T2, G7e/T3, and G7e/T4 Falke torpedoes were, with the exception of the T4 model, the standard torpedoes for Germany during World War II. All of the G7e models shared standardized dimensions for all German torpedoes designed for use by U-boats during World War II, they measured 53.3 cm (21 inches) in diameter, 7.16 m in length, and carried a Schießwolle 36 (a mixture of explosives) warhead of 280 kg. All were powered by 100 hp (75 kW) electric motors and lead-acid batteries which needed constant maintenance to maintain their reliability. Additionally, the batteries of these torpedoes needed to be preheated to a temperature of 30 °C (85 °F) to operate with maximum speed and range, though generally this was a non-issue as U-boats had the element of surprise and often had the advantage of firing the first shot.

The T2 model of the G7e went in service with German U-boat fleets in 1936. In stark contrast with the G7a steam-driven torpedo, the T2 left no visible stream of bubbles to alert ships that they were under attack, and was virtually silent; however, these were the T2's only advantages over the G7a torpedo. In all other respects, the T2 was barely functional and performed marginally when compared to the G7a. Its range was much less than the G7a's: at only 3000 m; and it ran much slower at 30 knots (56 km/h).

Poor range and speed were not the T2's only problems. Both of its detonators were flawed. The magnetic influence mechanism, designed to allow the torpedo to run under the keel of a ship and detonate, breaking the ship's back, was inconsistent; often a T2 would detonate prematurely, or not at all. This led the BdU to order that all G7e/T2 torpedoes be fired only for contact detonation. However, the contact pistol of the T2 also malfunctioned; the British battleship HMS Nelson managed to survive almost certain destruction when three torpedoes from U-56 struck on her keel, two broke upon hitting and the other failed to explode. Captain Wilhelm Zahn of U-56 was so depressed by the evident futility of his efforts that he needed to be briefly relieved of duty by Admiral Karl Dönitz in order to compose himself, while the civilian Naval Ordnance Corps, responsible for torpedo development and maintenance, continued to insist the U-boat captains were somehow at fault. Estimates of the failure rate of T2 torpedoes for one reason or another range between 20% and 40%.