BoatBanter.com - View Single Post - Anyone know PSI to MPH speedometer factor?

In article ,
says...

"Gudmundur" wrote in message
...
Looking for 'how many PSI of pressure in the pitot tube equal
how many MPH indicated speed on my speedometer.

I have a very accurate source of air pressure and want to test
my speedometer to get an idea of how well it's in calibration.

TNX folks!
It's easier to use a GPS unit to calibrate your speedometer.

Got the laptop charged and ready for tomorrow. My GPS is powered from
the laptop serial port and Precision Mapper 3.0 GPS-Link shows my speed
over land, so I will have a look at the calibration of the speedo and my
pitot positioning on my boat.

This is an old AirGuide speedo removed from my father's old wooden
runabout and this speedo last saw daylight about 1967. I cleaned and
lubed the unit and installed it on my 15ft FourWinns open bow.
Just a little piece of boating nostalgia put back in service. To bad
dad is no longer around to see it go. (probably twice as fast as he
ever saw it going).