Submarines: Anti-Torpedo Systems
December 7, 2023: Torpedoes, like naval mines, are weapons that are largely ignored until there is a naval conflict and warships have to face the potential use of mines and, worse, torpedoes. At that point it will be realized that efforts to create effective defenses against mines and torpedoes are not sufficiently abundant. Mines are less dangerous because they can be detected and neutralized. This requires precautions taken in advance, but if you want to avoid losses to mines you have to take the time to deal with them. Torpedoes are another matter. Mines are relatively cheap and plentiful. That means many nations have them and use them if there is a conflict and an opportunity to use the mines.
Torpedoes are more expensive than mines and more difficult to use. Torpedoes are different in many other ways. Their effective use requires very close proximity to the target. Damage is caused when the torpedo detonates via impact or from a magnetic detonator that triggers an explosion when the torpedo is close enough to the ship to inflict damage. In essence, a torpedo attack from a submarine hasn't changed much since World War II. You get in reasonably close, often within three kilometers, and you launch the torpedo. This cuts down the time one has to deal with the incoming threat.
Underwater sensors have a much shorter range for detecting incoming torpedoes. In order to reliably take out an incoming torpedo, one needs to see it. The "eyes" underwater usually consist of passive sonar - in essence, underwater microphones, with operators who try to pick out the torpedo in the whole underwater cacophony that includes whale songs, the ship's own engines, and other sounds of the sea. Active sonars can also be used, but, like radar, they also tell everyone where the ship using them is. Sonars have shorter ranges than radars, especially as submarines get quieter. Submarines are often considered to be the original stealth weapons.
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