World War II Database

Country of Origin	United States
Type	Torpedo
Diameter	533.000 mm
Length	4.950 mm
Weight	1005.000 kg
Range	3.700 km
Machinery	Alcohol-Water Steam Turbine
Explosive Charge	225kg TNT
Speed	67.00 km/h

Contributor: David Stubblebine

ww2dbaseThe United States Navy's Mark 10 Torpedo, as distinguished from the Mark 10 Mine, was planned as a fast, short-range torpedo meant for launch from submarines. Developed in 1915 by the E.W. Bliss Company and the United States Naval Torpedo Station at Newport, Rhode Island, it was a follow-on design to the nearly identical Mark 9 torpedo designed for launch from surface ships. The actual production of Mark 10s was done at the Naval Torpedo Station and it had the largest warhead of any torpedo developed by the United States up to that point.

As a World War I-era weapon, it was first assigned to the World War I-era R-class and S-class submarines, some of which remained in service into World War II. The torpedo model for submarines that followed the Mark 10, the Mark 14, was four feet longer and too long for the torpedo tubes of the R-class or S-class submarines. Both torpedo models were the same diameter, however, so the reverse was not true; the submarines capable for firing the longer Mark 14 torpedoes could, with minor adjustments, also fire the older Mark 10s. With the excruciatingly slow production rate at the Naval Torpedo Station, the Navy's inventory of all types of torpedoes at the outbreak of World War II was very limited. As such, in the early days of the war, fleet submarines were armed with both types of torpedoes, sometimes both at the same time. When the performance problems of the Mark 14s began to present themselves, some submarine commanders preferred to carry the older Mark 10 over the newer Mark 14, believing they were more reliable.

The Mark 10's principal advantage over the Mark 14 was in their exploders. The exploders of the Mark 14s were combination contact/magnetic exploders, and there were problems with both features. The exploders of the Mark 10s were straight contact exploders and were much more dependable. However, the Mark 14's other performance problem, its tendency to run deeper than the depth setting, was shared by the Mark 10. This problem in both models was suspected early on and was proven by Jun 1942 through Admiral Lockwood's unauthorized torpedo tests in Australia. Before final corrections to the depth control could be made, the solution in the field was to simply set the torpedo's depth to zero. This was done by several submarine commanders, with or without authorization from superiors, and produced better results.

As an older torpedo model during World War II, far fewer Mark 10s were used in combat versus the later models, but at least 300 Mark 10s were fired at enemy vessels in both the Pacific and the Atlantic. They sank at least 150,000 tons of shipping, including the first major Japanese combatant ship sunk by an American submarine, the 7,000-ton heavy cruiser Kako in Aug 1942. When the last of the S-class submarines were withdrawn from service in 1945, the Mark 10 was also withdrawn.

Sources:
United States Navy
Naval Weapons of the World (navweaps.com)
PigBoats.com
The Pacific War Online Encyclopedia
Wikipedia ww2dbase

Last Major Revision: Feb 2025

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10 Aug 1942

USS S-44 spotted a group of four Japanese heavy cruisers at the distance of 800 meters about 90 miles east of Kavieng, New Ireland at 0750 hours. At 0806 hours, she fired four Mark 10 torpedoes, scoring three hits on heavy cruiser Kako. Kako sank at about 0815 hours; 34 were killed, 582 survived.

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