149. Refinement of AI escorts in determining likely position of an attacking u-boat from torpedo wakes.
If the attacked merchantman is sunk within a short period of being hit, all the escorts should be aware of is the 180 degree arc "side" that the torpedo has come from, and therefore those escorts on that side should turn outwards from that side, and commence asdic and hydrophone searches. However, as the distance from which the torpedo is fired is unknown, the distance outwards they travel is fairly short.
If the merchantman is hit but does not sink quickly, it is assumed that the approximate track of a steam inbound torpedo is known to the crew, and this information is given to the escorts via short-wave radio or other signal, and the AI escort then proceeds along the reciprocal of that track, for a reasonable distance, likewise at asdic and hydrophone speed.
Similarly, if the track of a steam torpedo is seen passing an un-hit merchantman, the same reasonable distance is covered by the outbound pinging/listening escort, however, with a less certain bearing, so there should be a random error in bearing to course travelled.
If the u-boat is physically spotted, the AI escorts would travel directly at best speed to the area, for perhaps 90% of the distance, and only then conduct asdic and hydrophone searches, firing guns at the u-boat so long as it or the periscope is in view, possibly with star-shells.
So, firing electrics, will result in poor ability by the escorts to locate a u-boat, provided it remains quiet and achieves sinking hits. On the other hand, if it fires and misses with steams, or hits but does not outright sink, a merchantment, then the ability of the escorts to determine the location of the u-boat improves. Finally, if the u-boat is visually seen, then it's in for a world of hurt, possibly with several escorts coming for it at up to 36 knots....
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