John P. Cromwell attack technique on order

[Nisgeis]

Originally Posted by Joe S

Back in the days of Sub Battle Simulator, I used a manual plot and the following forumula for a firing solution: Range to track, at point of torpedo hit, divided by torpedo speed, equals torpedo run time to target. Run time to target X Target speed = distance travelled by target during torp run. plot the distance travelled by target back along its track from the point of impact and when the target gets to that spot you fire the torpedo It really doesnt matter what the aob is . It seems like this Cromwell method is based on the same idea. Based on my experience with Sub Battle Simulator (we're talking hundreds of hours) , I know it is a good method.My question is, what is the importance of the 45 AOB? I really dont think it makes any difference, except that the smaller the angle the smaller the profile of the target at the point of impact. The video and written instructions are great, good job! Joe S

Hi Joe S,

45 degrees is just a point at which the target's lengt is about 75% of what it would be broadside, but you also get the added advantage that 70% of the target's speed gets added to the closing speed of your torpedo, which is a big help. The 45 degrees works even better if you use a spread from aft to bow, as all the torpedoes arrive at the same time.

You can use this method though to attack any angle you want, even from behind.

Thanks for saying about that method you use and yes, it's essentially the same procedure you used to use on Sub Battle Simulator (sounds great :-). The only slight difference is, this is slightly simplified. All we need to find is the ratio between the two closing distances. For that, where you are using distance target travelled, versus distance torpedo travelled, we are taking that equation and simplifying it just a bit.

We are trying to find the angle formed by the two distances travelled, prior to collision for an unspecified unit of time. Your method of using distance travelled by target and distance travelled by the torpedo is great and will give you the correct answer. We can simplify that a bit though, as speed = distance * time for both target distance travelled and torpedo distance travelled, then we can say that the time component of each equation is the same. So, we can substitute it for a value of one. Thus the ratio between distances travelled becomes the ratio between speeds. That simplifies things a bit, as we don't have to work out how far things have travelled, only how fast .

Do you still use this method? If so, does it still serve you well?