Formula for speed?

[totodog]

What exactly is the formula to calculate the speed of a boat? I know range uses tangent(angle) = mast/distance, and the AoB can be calculated using some angle measurements. Could anyone tell me the formula for the speed of a boat? Thanks.

[Sag75]

I don't know the formula, but I'm sure it uses the bearing variation of the locked target, AoB and range.

[JMV]

Have a look there, may be you find what you need ( 08:17:09 ) :

http://www.subsim.com/radioroom/showthread.php?t=154918

Something like this may be :

Metric : 1852m / 3600s = .51 (constant). 1/.51 = 1.96 (constant)

When the answer is in meter per second we can either multiply by 1.96 or divide by .51 to get knots.

therefore,

2.3 mps / .51 = 4.5 knots

Imperial: 2026 yds. / 3600 s = .56 (constant). 1/.56 = 1.78 (constant). Either divide yds. per second by .56 or multiply by 1.78 to get speed in knots.

There are more examples in the ditto thread.

[Snestorm]

Speed x Time = Distance
Distance over Time = Speed