A QUESTION OF TORPEDOES...
In the 1890s the automobile torpedo (or mine) has some basic problems that it's inventors must solve before it can be effective as a naval weapon of war.
a. it must float with a slight negative buoyance.
b. it must travel in a manner so that its nose does not bob, nor wander off preset course left or right (nose wander).
c. It must not rotate longitudinally along its long axis nor roll along its beam.
d. it must maintain consistent depth.
e. it must maintain constant speed and travel a reasonable length of time to intercept and reach a moving target.
f. and if (not when, because this is the 1890s and getting a torpedo to behave is almost impossible) it hits it should blow a hole in the ship it hit.
Long before missiles come into the military cognizance with the inherent problems of choosing lead pursuit or lag pursuit logics, with the corresponding problems of fore, mid-body, or tail control, the inventors Giovanni Lippis and Robert Whitehead struggled unsuccessfully to solve these problems. One should not blame them too much, because as late as 1944, torpedoes demonstrated in practice that they would not work the way their inventors thought they would (Ralph Christie and the Marks XIII, XIV and XV torpedoes being the American example of WW II.)
As a practical matter, the other problems being secondary to the automobile aspect of the torpedo, there were/are three methods available to our heroic inventors to provide motive power. Two involve stored potential energy, and one involves transmitted energy:
aa. a flask of compressed air that is controlled in release to drive a fan turbine which in turn drives a screw. This is the Brotherhood air engine which is the motive heart of the Whitehead (British), Schneider (French), Silurico (Italian), and Schwatzkopf (German) torpedoes.
bb. a flywheel which is spun up to store potential energy to drive a power take off shaft through a log function reduction gearing and clutch system that impels constant controlled work throughput to the torpedo screw. This is the heart of the Howell Mark I torpedo, an RTL solution that the USN adopted in the early 1890s. That heavy flywheel, because of its mass and high rpm needed, also acted like a stabilizing gyroscope in the longitudinal and lateral nose wander fashion, although it did nothing for depth control. The torpedo would run a stable drift right curve and it would run hot (unless it sank, there was a depth control problem). The blasted thing could intercept a ship more reliably than a Whitehead. But then it would run deep, or if it hit, the detonator would fail, and it was so damned loud, you could hear its banshee wail from a mile away.
cc. or you could transmit electricity along an insulated cable that unreels behind and carries current to the torpedo and let the onboard torpedo electric motor do its thing. The Howell Mark II uses that method.
Electric torpedoes are silent, leave no bubbles to point straight back at who launched them and once you solve the depth control problem and the nose wander problem make ideal ship-killers.
The USN buys some Schwartkopfs in 1894 and takes them apart. No gyro control, so nose wander remains an issue (for everybody else too) but here's the thing. The Germans have a good hydrostatic flow pressure sensor that they incorporated into that fish. They also have an inertia hammer detonator that works at wider angles than the contemporary British, French, or Italian torpedoes.
The Americans have (in this AU) finally solved that cylinder roll problem with a complex contra-rotating propeller thruster in a shrouded tail control unit, (See the subs above.) and as long as they can get close, (about 1500-2000 meters lead pursuit angle) their right hand curve torpedoes with preset locked tail fins will run at constant depth to meet their targets.
The Howell Mark II comes into service around 1895. Note when the destroyer and submarine programs take off?
Mister McKinley's Navy is not too much different from Tom Jefferson's ideas on the subject.
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