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Can GPS be fooled?

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Old 11-11-2002, 12:10 PM
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More positive rake helps bow lift. Not sure if cup will have anything to do with it. Generally, the bigger the blades, the more bow lift. Once in a while, Ill run into some of the old ss michigan wheels they used on the old scarab 3's and they have serious bow lift.
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Old 11-11-2002, 12:16 PM
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My Merc mechanic has a prop that he referred to as a "raker" that I was going to try. He said they were used a lot on outboards, and I think the diameter had been cut down some. Doubt if I can spin it; I think he said it has a 24" pitch - too much for my mill with 1.36 gears.

Anyone have a set of 1.5's for sale?
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Old 11-11-2002, 12:35 PM
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On the river in downtown Chicago I have seen strange speeds and course info. The signal get bounced around when surrounded by sky scrapers.
 
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Old 11-11-2002, 02:24 PM
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GPS CAN BE INACCURATE.MY BOAT DOES 90 MPH BUT MY GPS SAYS 80 SOMETHING
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Old 11-11-2002, 02:44 PM
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As long as you have three birds locked in it will be accurate. The problem is mainly with the max speed, which is accurate but it may not be in the direction you think. If your GPS says 80, then my friend you are doing 80.
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Old 11-11-2002, 02:44 PM
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What?, did you have you're boat on the trailer, being towed by a GM truck? And besides any more you're GPS never gets above 48 mph
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Old 11-11-2002, 03:02 PM
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Hmmmmm..
My understanding of how a GPS works in that it locks on a location at set intervals (once a second for arguments sake). The mathmatical calculation of the disctance between the captured locations and elapsed time is how fast your going (MPH).
Because of this current in a river will effect your speed. If your going with the current your traveling at your boat speed+the speed of the current resulting in a higher total speed. The reverse would aply if going against the current.
I also thought you needed a minimum of three satalites to get a position. My Garmin GPSIII+ usualy hits 5 or more. If you were to lose contact and only have two satilites to track from I dont think the unit would have enough data to calculate.
I have seem these units give highly suspect reading (Max Speed).
The error being at 100mph+ I dont believe that its being effected by the boat being towed
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Old 11-11-2002, 03:07 PM
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I had a hand held GPS in my suburban that said I was going a max of 125 mph while driving throught the keys. I don't recall going over 60 mph!
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Old 11-11-2002, 03:09 PM
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Hey brad,
Slow that thing down and pay attention.
Maniacs in their hoped up cars...I tell ya
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Old 11-11-2002, 04:42 PM
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Yeah, if it came back with a reading of 125 MPH, I would know something was up! Since it was only about 6 MPH over the speeds that I had seen before, I thought there could be some possibility that it was legit.

I suppose the current could have had some effect. Water was up, and current was pretty swift. But I would also expect the 25+ MPH headwind to offset that some, too.
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