Also known as "Ato," this torpedo was issued throughout the war and was considered to be very reliable. It was developed almost directly from the 50 cm (20") G7 of World War I and differed from those of other nations by using Decalin (decahydronaphthalene) instead of kerosene for fuel. Producing this torpedo took about 3,730 man hours per torpedo in 1939 but this fell to 1,707 hours by 1943. This was significantly more than what it took to produce the electric G7e.

The 44 knot speed was found to overload the engine and was not used during the early years of the war. The early models used in 1939 had ranges about 20% less than those given above. Used a four-cylinder radial engine that drove a single six-bladed propeller.

The Federapparattorpedo (spring-operated torpedo) or FAT variation had a simple guidance system that allowed a series of long or short legs or loops at the end of a configurable length of straight course.

Starting about mid-1944, the Lagenunabhängiger Torpedo (LUT) variation was introduced which was a more sophisticated version of FAT. LUT could be fired at any target angle and could follow a curved path to its target. LUT had problems with the targeting gear not disengaging at launch, resulting in "tube runners" and appears to have been rarely used after December 1944.

A Note on Sources: Warhead weight for these torpedoes conflicts in many references. I have seen numbers as low as 617 lbs. (280 kg) and as high as 948 lbs. (430 kg). It is possible that the lower numbers were for torpedoes issued early in the war and then heavier warheads were introduced during the war. However, I believe that the correct warhead weight was 617 lbs. (280 kg) as shown in the table.

Also known as "Eto," this unit used a 8-pole, 110 Vdc electric motor developing 100hp that drove a pair of contra-rotating two-bladed propellers. The above range and speed could be reached only if the batteries were preheated to 30 degrees Celsius. These torpedoes had to be serviced every three to five days in order to maintain their reliability. Slower than the wet-heater G7a type, but trackless and relatively quiet. It took about 1,255 man hours to produce each torpedo.

Each torpedo held 60 two-volt batteries coupled in series. Total Battery voltage was 124 Vdc immediately after charging and this decreased to 115 volts two days later. The voltage dropped to 104-106 Vdc during the run.

A Note on Sources: Warhead weight for these torpedoes conflicts in many references. I have seen numbers as low as 617 lbs. (280 kg) and as high as 948 lbs. (430 kg). It is possible that the lower numbers were for torpedoes issued early in the war and then heavier warheads were introduced during the war. However, I believe that the correct warhead weight was 617 lbs. (280 kg) as shown in the table.

Many records on these torpedoes were lost when the Gotenhafen experimental station was demolished to prevent capture by the Soviet Union. Serious experiments on homing torpedoes began in 1936.

T4 Falke

The first passive homer. Homing was by a simple noise measurement. Intended for use against merchant ships so the low speed was acceptable. Originally known as G7eS, with the “S” signifying “Sonderartsführung” (special manner of behavior).

T5 Zaunkönig 1 (wren)

Known as GNAT to the British. For use against convoy escorts. Designed to home in on cavitation noise of around 24.5 kHz which was equivalent to propellers on an escort traveling at 10 to 18 knots. First successful combat use in September 1943.

T5a

A modified T5 used by S-boots (E-boats).

T5b

Same range as T5a but used by submarines.

T10 Spinne

A standard torpedo modified to use wire guidance. First issued in 1944 but the results were not satisfactory.

T11 Zaunkönig 2

Improved T5 less influenced by Foxer (towed noise maker).

The F5 was a low-performance Norwegian Torpedo developed by Schwarzkopf. Dropping speed was 75 knots from 50 - 80 feet (15 to 25 m).

The F5b was in service from late 1941 to the end of the war with relatively minor changes. To control flight in the air a wooden K3 tail was used that broke off when entering the water. This was replaced in 1944 with L2 which was similar but had ailerons operated via a heavy gyro. The L2 tail permitted increased dropping speeds and heights, the maximums actually achieved were 183 knots and 390 feet (120 m). The differences in weights and lengths in the table above are due to the different warheads.

This was the German designation of the Italian Fiume torpedo "W" and was used in large quantities before the 5b was available.

"Schlachtschiff Tirpitz" by Jochen Brennecke
"Naval Weapons of World War Two" by John Campbell
"S-Boote: German E-boats in action 1939 - 1945" by Jean-Philippe Dallies-Labourdette
"Black May" by Michael Gannon
"Una nueva visión del hundimiento del submarino C 3" [A new vision of the sinking of Submarine C 3] by Jose Luis Martín
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"German Torpedo Bombers? What Were they?" forum topic from WW2inColor.

30 May 2008 - Benchmark
07 January 2012 - Added G7a pictures
22 January 2012 - Altered note about G7a and G7e explosive charges
05 October 2019 - Converted to HTML 5 format
24 December 2022 - Added details on G7a and G7e torpedoes, added source and two "Note on Sources"