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rune711 · 04-17-07, 01:59 AM

I am not understanding why my speed estimates are always so far off. I'm using the standard method of plotting several sightings of the target, measuring and then using these figures to compute the speed. Distance = rate * time. In this case I need to figure rate, so it's Distance/time = rate.

For example if I see that the target has moved 1.5nm in 3 minutes that should give: 1.5/3 = x knots. A knot is measured in nautical miles per hour, so thats

1.5/3 = x/60 equals 20 * 1.5 = x or 30 knots.... which is twice the actual of 15 knots. The ruler IS in nm, right? Or is it in 1000s of yards or meters, or what???

What am I goofing up?

04-17-07, 01:59 AM	#1
rune711 Swabbie Join Date: Apr 2007 Posts: 8 Downloads: 0 Uploads: 0	Newb question: target speed. I am not understanding why my speed estimates are always so far off. I'm using the standard method of plotting several sightings of the target, measuring and then using these figures to compute the speed. Distance = rate * time. In this case I need to figure rate, so it's Distance/time = rate. For example if I see that the target has moved 1.5nm in 3 minutes that should give: 1.5/3 = x knots. A knot is measured in nautical miles per hour, so thats 1.5/3 = x/60 equals 20 * 1.5 = x or 30 knots.... which is twice the actual of 15 knots. The ruler IS in nm, right? Or is it in 1000s of yards or meters, or what??? What am I goofing up?