The Mark 18 was built in competition with the Bureau of Ordnance electric torpedoes, which had been in development at the Naval Torpedo Station, Newport, Rhode Island, since the 1920s, in particular the Mark 20, originated in 1941 in collaboration with General Electric and Electric Storage Battery Company. In 1942, several German G7e electric torpedoes ran ashore, leading CNO, Admiral Ernest J. King, to prod BuOrd into building an electric torpedo for the U.S. Navy's own submarines. BuOrd told NTS to get the Mark 20 in shape, or drop it in favor of a copy, with the primary emphasis being speed of introduction. "Newport, typically, preferred its own finely machined project", but neither General Electric nor NTS had the facilities. As a result, BuOrd turned to Westinghouse Electric & Manufacturing Company, which on 10 March 1942 got all data and designs for electric torpedoes NTS had produced so far. Westinghouse quickly decided to copy the G7e, and "went to work with a speed and fervor that was dazzling". Design was complete by mid-April, and a contract for 2,000 Mark 18s, 2,020 warheads, 543 exercise heads, tools, spares, and workshop gear was issued 2 May. The first test models were delivered just 15 weeks after Westinghouse started work and the Mark 18 was promised to the Submarine Force by summer 1942.
Problems
The batteries did not deliver hoped-for performance and gave off too much hydrogen gas, and there were bugs in production, in part because of the fine tolerances necessary and the need to use unskilled labor. NTS, as usual, "offered no help", refusing even to pass on trial data. Trials, supervised by Commander Oliver G. Kirk, aided by "Spike" Hottel, did not go well. Eli Reich, Lapon's exec, described NTS's attitude as near to sabotage. Kirk and Reich drafted a scathing memo, which ended up on the desk of Admiral Lockwood, who took the matter to William H. "Spike" Blandy, Chief of BuOrd, who agreed to push the Mark 18 ahead.
Deployment
The first submarines to use Mark 18s were Eugene Sands' Spearfish and Mush Morton's Wahooin September 1943. Sands "experienced enough torpedo problems to drive an ordinary man berserk": one sank, one broached and ran wild, three fishtailed at launch and hit the outer doors before disappearing, and seven missed astern. His results, as described by his squadron commander, "Gin" Styer, "were disappointing".
Characteristics
The main advantage was that 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, the need to regularly withdraw the torpedoes from their tubes for recharging, sensitivity of the batteries to water temperature, and onerous maintenance procedures. The Mark 18 shared one major flaw with the Mark 14: it had no protection against circular runs, a defect which claimed Tang for certain, and possibly other U.S. submarines, as well; "Donc" Donaho's Flying Fish was nearly sunk by a trial model in October 1943. Some 30% of torpedoes fired by U.S. submarines in the Pacific War were Mark 18s. The design was dropped from service in 1950 in favor of faster and more reliable later types. The Mark 18 was long, weighed, had a warhead of of Torpex with a contact exploder, and had a speed of and a maximum range of. By July 1944, an improved version had appeared.
