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N7KTP > NAVNET 03.01.05 09:35l 66 Lines 3783 Bytes #999 (0) @ WW
BID : 31191_N7FSP
Read: DG8DG OE5TUN GUEST
Subj: TORPEDO MK-24 ("FIDO")
Path: DB0FHN<DB0MRW<DB0FSG<IN3TRX<IW3AQL<I4UKI<IK5CKL<IW2OAZ<IZ0AWG<CX2SA<
HG8LXL<7M3TJZ<N7FSP
Sent: 050102/2348z @:N7FSP.#SEA.#WWA.WA.USA.NOAM West Seattle, WA. on 145.010
FROM AMERICA'S LAUNDRY ROOM TO UNDERSEA WEAPON
The Mark 24, code named Fido, was the first acoustic torpedo
developed by the United States. Fido was considered one of the three
most successful torpedoes of World War II. (The other two were the
steam turbine Mark 14 and the electric Mark 18.)
In 1942, in response to a German Naval Acoustic Torpedo (GNAT),
the Naval Defense Research Committee sponsored a multi-organization
research and development project, which culminated in the historic
development of an airplane-launched torpedo that used acoustics to
pursue a target. This acoustic torpedo development project was given
the code name Fido using the word 'mine' to mislead enemy intelligence;
the word 'torpedo' was never said aloud. The Fido was a forerunner of
the submarine-launched Mark 27, nicknamed Cutie, and the echo-ranging
Mark 32 torpedoes.
Several companies were involved-some cooperatively and some
competitively-to develop this weapon from the ground up. Bell Labs and
Harvard Underwater Sound Laboratory worked on the homing system; Bell's
manufacturing division, Western Electric, worked on a battery; General
Electric tackled the propulsion and steering motors; the David Taylor
Model Basin was tasked with outer shell development; the
Columbia University Sound Laboratory was also involved in the research
and the entire project was overseen by the U.S. Navy.
The requirements included electric propulsion; short running time
(10-15 minutes); a small explosive charge to cripple only; a small body
for aircraft delivery; and passive acoustic control. The torpedo had to
be fast enough to overtake a submerged submarine yet slow enough to
allow the torpedo to hear the noise of the submarine. The level of
understanding of acoustic technology was in its infancy but before the
end of the war Fido would become one of the Allies' most important
weapons.
For propulsion General Electric found one of their 7.5 horsepower
commercial washing machine motors worked with little alteration. By
contrast to this off-the shelf technology, the acoustic researchers had to develop technologies never thought of before. But th
rough perseverance, under the pressure of war, a few pre-production prototypes were manufactured in August 1942 and tested in S
e
ptember. On December 7, 1942, for the first time in history, a torpedo launched from a plane used acoustics successfully to pur
sue a target. The United States' first lethal use occurred just a few months later on July 14, 1943.
The directive on the torpedo's use specified that it could only be
employed after the target submarine had submerged. This tactic would
keep the Germans from realizing that this was a target-seeking weapon.
Enemy submarines were fired upon, forcing them to submerge; Fido was
dropped at the froth of the dive spot and homed in on the propellers to
cripple or to damage the submarine. A second torpedo was sometimes
dropped to complete the job. The effectiveness of a depth charge to
sink a U-boat was 9.5% as compared with the Mark 24 at 22% success
rate.
A secondary invention spawned by this development process was the
beeper which allowed for torpedo recovery. This device by itself has
been said to be valu1able enough to pay for the total research and
development of the entire program.
This listen-only aircraft-launched weapon was adapted to create
its counterpart, the passive submarine-launched Mark 27, nicknamed
Cutie. The Cutie's capability was parallel with the German GNAT.
The Mark 24 also laid the groundwork for the echo-ranging Mark 32
torpedo. The Mark 32 was a Fido look-alike that would see service as an
antisubmarine torpedo launched from aircraft and destroyers.
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