How do you... measure Speed?

[niterider1]

According to Eagle Tree they have three ways to measure ground/water speed. One is GPS second is using wind speed through an air pitot tube and the third uses a waterspeed pitot tube that somehow goes on the bottom of the hull. I guess the third one works if there is standing water with no current.
I think that if you just want an estimate of the speed this system would be ok, if you are going for a record you would need alot more people, money and equipment or a sanctioned speed testing event!

[Boaterguy]

if there was a current, it wouldn't affect the reading much, if in water, the boat is still travelling the same speed through the water.
say you have a 20mph boat, running in a 20mph current, the boat would be stationary, but the water speed would still be 20mph.

[properchopper]

At Legg Lake, there are many ducks that, after so many SAW's, will swim alongside our boats at speed. Then we guess the speed of the duck.

[Boaterguy]

so, you don't go mach 2, 3 or 4, you go duch 2, 3 or 4? the typo is on purpose

[tanasit]

I noticed my radar gun sometime picked up the speed of the rooster tail, thus gave the much higher speed readings. Later to confirm that I bought a GPS and used both and sure enough the GPS read 43.4 but the radar says 73.4!!