Quote:
Originally Posted by TorpX
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I used to use the following formula:
speed (kts.) = .59 target length (ft.) / time(sec.) + sub speed(kts.) * sin target bearing
if your sub and target are going in opposite directions then the last term sub speed(kts.) * sin target bearing is subtracted.
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Hi TorpX,
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...i believe that this formula is wrong for getting target's speed,TorpX !
the problem is not so simple for been solved by this simple formula.
where did you find this formula written ? before i proceed and explain why this formula is not correct i would like you to explain it more detailed (for example write the formula more clearer or show with a little example how you are using it and getting speed)) becuase ,maybe, i am missing something at the way you have written this formula.
ps: if you can prove the above formula...would be even better.
sorry for being the 'Doupting Thomas' here but this formula is not working, TorpX. and there is no way to make it work becuase you are not considering the target's course (relative to your own course) factor which is a very important factor ! this factor has equal importance with your boat's speed factor (which you are correctly considering) and has ,also, equal importance with the bearing to target factor (which,also, you are correctly considering).
as i said ,is not so easy problem . a good tool that help in situations like this is the back side of attack disc (in case that we don't want to use digital-modern-calculators)
ps: @TorpX : don't feel offended ...i will be huppy if ,at the end, prooved to be me on the wrong side.