Quote:
Originally Posted by Bothersome
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To give a better scenario to this let me use actual data. Convoy coming in going south to 180, 11 knots. 750 yard spacing fore and aft and beam. Basically a big 5 x 5 positional layout. I get on the east side facing 300 degrees (60 degrees to the convoy). I set up my target line 15 degrees starboard because I'm using 29 knot electrics. This makes it about 0 degree torpedo angle. The plan worked nice except that once that first ship takes a hit. The whole convoy slows way down and start evading. Firing 6 as 6 different ships pass my line, 3 miss and 3 hit (3 different ships). The intent was to cripple as many ships as possible to "clean-up" later. One ship, an old tanker 7100 tons goes down after about 20 minutes. Of course I didn't get to see it, cause was about 530 feet under water trying to evade some ash cans myself.
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I am curious where the torpedo hits the first ship. And if it in fact was the first torpedo launched that hit.
As I can't help but think (calculate) that looking 15 degrees starboard at the time of firing is NOT going to get the torpedo in the right spot based on 11 knots target speed, 60 degrees AOB and 29 knots torpedo speed. If one does the numbers correctly then the periscope would need to be set at 19 degrees and a bit.
lead angle= arcsine ( 11 * sin(60) /29 ) = 19.2 degrees
Now, if you are close enough the target size might still be enough to get hit towards the aft section. But likely not where you intended it. Are you sure of your speeds? Or used an offset angle in the process?
Once the other vessels notice the first one being hit then they do manoeuvre and get out of the way. So you need to try to get the hits almost simultaneously. For this you would need to fire on the most distant first, and in the same row (next to one another). With the intended setup this would happen automatically, the most distant target should be in your cross-hairs first. Then wait for the closer ones in the same row to be on your crosshair. This won't happen with targets in the same column (behind each other). Equally not likely to work for targets that are positioned diagonally in the convoy, as it is a combination of the two. Keep those for your next attack run when attacking a different row.
[EDIT]And 60 degrees might be a bit too much of a stretch for this to work. The target in the closest column might not get on the periscope line before the first torpedo already hits the furthest one. It works much better when shooting perpendicular to the target course.
[EDIT 2] The more I think about it, simultaneous hits work ONLY when the torpedoes are moving perpendicular to the target course and to one row only. I'm sorry, but the geometry dictates it.