| United States Navy submariners stow a Mark 18 torpedo for later use prior to a patrol. The Mark 18 was the Westinghouse version of the captured German G7e. It had the advantage of being trackless and only requiring about 70 percent of the labor needed to build a wet-heater torpedo. However, its poor performance and design flaws led to it being discarded in 1950 in favor of the Mark 14 and Mark 16. Until new guide studs were placed in the tubes, the Mark 18 was susceptible to damage upon launch because it accelerated much faster than did the conventional steam-powered torpedoes. By the end of the war, the Mark 18 made up 65 percent of all torpedoes fired by submarines and in total, 30 percent of all the torpedoes fired in the entire war. The Mark 18 did not produce a wake of bubbles or turbine exhaust pointing back to the submarine firing it – a major advantage in daytime engagements. The torpedo also lacked the depth-keeping and exploder problems that had plagued the Mark 14. The disadvantages were the low speed compared to the Mark 14’s 45 knots (11 kilometers an hour; 52 miles per hour), the need to regularly withdraw the torpedoes from their tubes for recharging, sensitivity of the batteries to water temperature, and constant and onerous maintenance procedures. The Mark 18 shared 1 major flaw with the Mark 14: it had no protection against circular runs, a defect which claimed USS Tang (SS-306) for certain, killing 78 United States Navy personnel, and possibly other American submarines, as well; Glynn R. “Donc” Donaho’s (March 25, 1905 – May 26, 1986), USS Flying Fish (SS-229) was nearly sunk by a trial model in October 1943. The Mark 18 was 20 feet (6.1 meters) long, weighed 3,154 pounds (1,431 kilograms), had a warhead of 575 pounds (261 kilograms) of Torpex with a contact exploder, and had a speed of 29 knots (54 kilometers an hour; 33 miles per hour) and a maximum range of 4,000 yards (3,700 meters). By July 1944, an improved version had appeared. 8,500 Mark 18 torpedoes were ultimately produced. | |
| Image Filename | wwii1837.jpg |
| Image Size | 77.32 KB |
| Image Dimensions | 500 x 500 |
| Photographer | |
| Photographer Title | United States Navy |
| Caption Author | Written or Adapted by Jason McDonald |
| Date Photographed | January 1, 1944 |
| Location | |
| City | |
| State or Province | Midway Atoll |
| Country | United States |
| Archive | Naval History and Heritage Command |
| Record Number | United States Navy at War Page 42 |
| Status | Caption ©2026 MFA Productions LLC Please Do Not Duplicate or Distribute Without Permission; Image in the Public Domain |
Author of the World War II Multimedia Database