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Mark 27, U.S. Torpedo

Specifications:

Dimensions     
19" by 7'6"
48.3cm by 2.286m
Weight
720 lbs
320 kg
Range 5000 yards (4570m) at 12 knots
Warhead 95 lb (43 kg) Torpex
Propulsion
Electric
Production
About 3000


The Mark 27 "Cutie" torpedo was a modified version of the Mark 24 aerial homing torpedo, with wooden guidance rails that allowed it to be fired from standard 21" submarine torpedo tubes. It was intended as a "last-resort" defensive weapon against escort ships. In spite of its low speed and small charge, it had considerable success, scoring 33 hits out of 106 fired and sinking 24 of its targets.

The torpedo had a floor switch that kept it from diving below 30' (9m) to ensure that it would not endanger its own launch platform, since the torpedo followed a circular search pattern after launch and until it acquired a target (or ran out of power.) The Mod 3 version increased the warhead to 200 lbs (91 kg) and was programmed to make a straight run before beginning its circular search. In order to reduce the acoustic signature, the torpedo swam out of the torpedo tube under its own power rather than being ejected by compressed air like a conventional torpedo.

The Allies countered German acoustic torpedoes using towed noisemakers, but I have found no indications the Japanese developed any similar countermeasures.

References

Branfill-Cook (2014)

Campbell (1985)

Sasgen (2010)

Wildenberg and Polmar (2010)


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