G7es torpedo

TV: the original TV acoustic torpedo. TVa: variant of the TV for use by Schnellboote. This had a range of 8000 meters at 22 knots. TVb: variant of the TV for use against submarines. Had the same range as the TVa. TXI: improved version of the TV. This improved version had modifications that were intended to allow the torpedo to bypass enemy decoys and be less vulnerable to jamming.

SAET-50: first acoustic homing torpedo of the Soviet Union and based on the German TV torpedo. The torpedo was developed as a result of Soviet engineers gaining access to German torpedo technology during and after the Second World War. The SAET-50 entered service in 1950. Later modified with an improved battery; this torpedo entered service in 1955 as SAET-50M.

The acoustic homing torpedo required a minimum distance of 400 metres (1,300 ft) to lock onto the target after launch. The detection range of the hydrophones varied significantly according to circumstance, but 450 m (500 yards) was considered reasonable for a ship moving at 15 knots. After at least one unconfirmed instance of a U-boat (U-972) sinking after being hit by its own torpedo, and another circle-back that forced the U-862 to crash-dive, the BdU ordered submarines to dive to 60 metres (200 ft) and go completely silent after launching acoustic torpedoes, to minimize the risk. The first 80 TVs were delivered on 1 August 1943, and the weapon was first used in a large-scale maneuver against the North Atlantic convoys ONS 18/ON 202 in late September 1943. The commanders reported a number of torpedo strikes and recorded the sinking of nine commercial steamers and 12 escort ships after the battle. In fact, only six merchant ships and three escort vessels, a destroyer, a frigate and a corvette, were sunk. However, despite some initial success, in particular sinking destroyers and corvettes, the TVs effectiveness was quickly nullified by the introduction of a noise making decoy known as Foxer. The NDRC worked on countermeasures to an acoustic torpedo long before its introduction by the Germans. At the end of September 1943, it was promptly installed on all transatlantic escort vessels. Grossadmiral Karl Dönitz, not satisfied with the development of countermeasures, realized that his brief success against the North Atlantic trade convoys was only a flare up and recorded: [it is] finally clear that surface warfare for U-boats had come to an end. It was now a matter of filling in time till the new type should be ready for action. In spite of highly effective Allied countermeasures, a total of ca 650 TVs were fired in combat, sinking 77 ships.