another problem- what's going on here?

[ddiplock]

I've found myself a coastal merchant. Everything is perfect for a torpedo shot.

I'm gathering target data such as ship type, AOB and target speed. I understand in order to get a more accurate speed reading you're Uboat needs to be travelling slowly, and the longer you let the stopwatch tick, the more accurate the speed estimate of the target is.

My first speed reading was 7 knots.....not bad, seems a little fast, but reasonable. Bearing in mind i'm at ahead slow and crawling along at 3 knots myself. Took another speed reading, got 17 knots.....ok, that's not right. So i took a third reading and got a whopping 51 knots......ok something is definatly not right now.

What's up with this guys?

[panthercules]

Originally Posted by ddiplock

I've found myself a coastal merchant. Everything is perfect for a torpedo shot.

I'm gathering target data such as ship type, AOB and target speed. I understand in order to get a more accurate speed reading you're Uboat needs to be travelling slowly, and the longer you let the stopwatch tick, the more accurate the speed estimate of the target is.

My first speed reading was 7 knots.....not bad, seems a little fast, but reasonable. Bearing in mind i'm at ahead slow and crawling along at 3 knots myself. Took another speed reading, got 17 knots.....ok, that's not right. So i took a third reading and got a whopping 51 knots......ok something is definatly not right now.

What's up with this guys?

I'm not sure what the problem with it is, but I have completely given up on the stopwatch thingy - no matter what I'm doing I can't get decent/reliable speed readouts from it

Now, I just use some variant of either (1) the 3'15" "rule" (distance target travels in .1km increments over 3 minutes 15 seconds = speed of target in knots) or (2) plotting target's distance traveled and mine over any reasonably long period of time and then comparing how far the target went with how far I went (i.e., if I'm going 3 knots and target went twice as far as I did, then target's going 6 knots, etc.)

Also, I'm getting pretty good at estimating speed from the target's wake/bow wave (if the weather is good enough), or sometimes you can get close if your sound man reports target speed as slow (generally seems to be about 6-8knots), medium (generally seems to be about 10-12 knots, or fast (harder to tell, seems to be around 15-18, but I haven't had many examples of that to test that theory)

Good luck, and good hunting!

[Skubber]

The weird speeds seem to be related to an incorrect AOB entry (at least I think this is it.) The ship needs to be moving across your field of vision for this method to work, and and AOB of 45 degrees vs. say, 90 degrees will give you a different speed estimate.

So if you AOB entry is way off, the stopwatch-speed calculation will be too.

Originally Posted by panthercules

Also, I'm getting pretty good at estimating speed from the target's wake/bow wave (if the weather is good enough)

I do this, too, as a kind of "reality check". If I've calculated 5 knots, but there's a huge bow wave, I redo the calc. or make an adjustment.

And real sub commanders did this too, as I'm sure many of you know already – thus the fake bow waves painted on the foreward waterline of many warships...