1940 to 1949: Computing During World War II and the Postwar Era - The Technical and Social History of Software Engineering - page 65

and made precision bombing one of the most effective weapons leading to the Al-
lied victory, although not all results were successful.
Another effective analog computer developed by the United States was the
Torpedo Data Computer (TDC), used aboard all U.S. submarines. There were a
number of models of this device, but the Mark III and Mark IV were the best of
those during the war. The Mark III was operational in 1940, and the Mark IV was
operational in 1943.
These bulky devices were so important to accurate aiming that they were car-
ried in submarine control rooms and two extra, specially trained crew members
kept them operational. The Mark III and Mark IV torpedo-aiming devices are cited
as being the best of any country during World War II.
Unfortunately, the American Mark 14 torpedo was not as reliable as the Japan-
ese long lance torpedo when the war started, but it improved over time. The later
Mark 18 American torpedo was one of the best in the war.
The Mark 14 torpedo used a form of analog computer as a detonator, called the
Mark VI detonator, which included both magnetic sensors and contact detonation.
For reasons of cost, the Mark VI detonators were not given live tests prior to be-
coming operational. A great many American torpedoes hit their targets but failed
to explode during the first two years of World War II due to faulty magnetic det-
onation.
Another problem was that the initial tests of the Mark 14 torpedo used dummy
warheads, which were lighter than actual combat warheads. As a result, the Mark
14s in combat ran about 10 feet deeper than programmed, which caused many
misses.
It was only in September 1943 that the various problems of American torpe-
does were solved. Problems with the torpedoes were often found under actual
combat conditions, and the Bureau of Naval Ordnance ignored dozens of reports
from frustrated American submarine commanders. The final fixes required that
Admiral Ernest King, the Chief of Naval Operations, “lit a blowtorch under the
Bureau of Naval Ordnance.”
A naval base for spotting German submarines was established in 1942 on a
property adjacent to the torpedo testing area in Newport, Rhode Island. The build-
ings were designed to look like beach houses in order to conceal their purpose
from German submarines that might be approaching Narragansett Bay to attack
U.S. ships at the Newport naval base.