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Old 06-29-2011, 03:31 PM
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deminimis deminimis is offline
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Join Date: Aug 2009
Boat: 2004 X-Star
Location: PNW
Posts: 700
Its like air speed vs ground speed, just substitute water for air. For towing, over-land speed isn't important, its over water speed. If you board at 20mph on a lake with GPS and you're set up the same on a 2 mph river, then you're really boarding at 22 mph (water speed -assuming traveling up current). Then, when you turn and travel down current, you're only going 18 mph (water speed). So, your GPS based PP is roughly off the mark plus and minus the current's speed.
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Last edited by deminimis; 06-29-2011 at 03:34 PM.
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