That's right, you cannot know the speed if you don't have a range. And most time to observe speed accurately depends on how accurate the range is. What they're saying is you don't have to need to set the accurate range in TDC, and it doesn't mean you never need the range. You DO need the range, and as accurate as possible.

BTW, I'm interested in how people handle multiple targets at a time with these methods. And in real life, it seems dead stop waiting is not practical (difficult to keep the depth) when submerged. And when on surface, the German U-boat commander book suggest not to stay but always move, and I haven't yet read a story in which the commander waiting and lurking at the ideal fireing spot. Then, doing this realistically means everything is in motion and it doesn't seem too easy unless you can get VERY close.

A simple test....


Set up a solution on the TDC. For example set the speed to 8 knots and the AoB to 90 and bearing to zero. First, set the range at 500 and check the gyro.

Next, set the range to 2500 and check the gyro. Has the gyro changed? If so, the range is important for the shot, and the difference in the two gyro angles is the amount of error you would have in your solution with a 2000 meter error in your range estimation.

loads of help guys, im starting to hit...ocasionally,lol. Seriously though much thanx!

Here's another interesting situation...suppose your TDC was broken where range, AOB, and speed could not be entered :hmm:

...and your torpedos could only be fired straight ahead...

...then, just relying on math...

you might want to use the law of sines, i.e.,

Offset Angle of Collision (angle of lead) = ((Target speed / torpedo speed) x sin(AOB))

btw: you can determine speed by counting revs.

Cheers,

:huh:

I'm just suggesting that if you put your TDC in manual, where it doesn't function when the scope is turned, that is, all indications on zero. You've disabled the ability for the torpedos to turn, they only go straight out of the tube.

coveat: sub is perpendicular to track of target.

example:

ship speed = 8 kn.
torp speed = 30 kn.
AOB 90° green (strb)

Law of sines

Offset Angle of Collision = arcsin ((8/30)*sin(90)) = 15.5°

since the target is traveling left to right across your sight picture, when the MOT reaches 344.5° --you fire your torpedo(s).

you will score a hit no matter if the target is 500m or 5000m--provided it maintains a constant speed of 8 kn.

...also, do a search on Greyrider's sound trainer.

Its somewhat more clear now! Thank you...I'll play around with that rule this weekend and let you know how it went...:up:

Anyone know where I can find a training mission consisting of a single merchant intercept that starts off w/ a visual of say 10000 meters?

Thanks,
Barkhorn.

There's another factor too (at least with gas propelled torps) which is torp speed setting: at 500 m you can use fast settings but at 2500 you'd have to run them slow, which would also increase the bearing you'd have to fire from.

In my last mission I'd setup a manual spread for a 90 deg beam shot at 600 m but realized, when the target was at at a bearing of 330 degrees and I was still 2 km out from the point of intersection and closing at only 7 knots, that my preset 600 m fast speed set fan shot would leave my torps on fumes before they even got close to the target.

At that setting the "firing point" was bearing 352 and I quickly guesstimated I'd be more likely firing at about a 1600 m range - too far for fast torps. So reset them to slow, tightened the spread, increased the range to 1600 m in the TDC, and the solution increased to a 345 degree bearing (which his bow was just passing across by this time, I got the doors open & the torps out and scored 2/3 hits with one torp going wide). The bugger kept on chugging at 7 knots though (a C2 that I had to use impact settings on, 2 m depth, because of the weather) and later I did finish him with a 2nd fan shot from 600 meters at 8 degrees bearing with both torpedoes set to fast and almost cleaved the ship into thirds (instead he split down the middle in a very pretty and explosive display). 4 torps on a C2 is overkill I know but it was immensely satisfying all the same :)

Anyway I'd say range doesn't matter much at point blank (fast torps, range <600 m) but becomes more important as it increases and with slower torpedoes. But I'm still a novice to manual targetting so this is conjecture based on limited experience.