How well will GPS work in river water that is moving?

[myrtlebeachrider]

If a boat is going against the tide how will gps handle the boat speed?
The water under the boat and skier could be moving with or against them.
A paddle wheel system handles this issue.
What does everyone think? Course it only matters if you are in a river.

[Onevw2go]

RE: How well will GPS work in river water that is moving?

You are kidding right? GPS measures how fast the boat is moving, it doesn't matter what direction the water is flowing. that would be like asking, "will my GPS inthe car work if I am driving into a headwind"??

[NautiqueJeff]

RE: How well will GPS work in river water that is moving?

See the thread below for lots of information on this.

http://www.planetnautique.com/index....ewtopic&t=8963

[myrtlebeachrider]

If you are wakeboarding at 22mph and the tide is moving at say 5mph against you wouldn't that make you feel like you were riding at 27mph. Kinda like trying to stay beside a dock with the boat in gear because the water is moving. You're traveling 0 mph but your paddle wheel might say otherwise.

[wakeboardin2k4]

Rivers are tricky with speed control. What we do is we line up next to the dock with the boat in gear and see how fast we need to go in order to stay right next to the dock, in that same place. Then from there we adjust our speed that many miles per hour when going against the flow of the river, or with the flow of the river. Its not an exact science but it gets us close

[myrtlebeachrider]

That was sort of how I was thinking adjusting for the flow of water. I'm not against gps based speed control. I wakeboarded at Shaun Murray's house behind his 230 and the Zero Off was right on. I was impressed at how well it handle speed control. It could be set at any tenth of a mph versus every other.

[Laptom]

GPS is a cool feature. But I really hope that Zero Off would get an extra mode for running on rivers (paddle wheel)... Can you still get Perfect Pass on new boats instead of Zero Off?

[NautiqueJeff]

Yes, PP is still available on new boats as an option.

[bkhallpass]

Perhaps I'm not understanding how zero off works. However, given that zero off is GPS based, I don't
understand what difference it would make if you are running on a river. In fact, one of the advantages of a GPS system would seem to be that you wouldn't have to spend a bunch of time calibrating for current. Perhaps someone can enlighten me. BKH

[NautiqueJeff]

He's more concerned with speed over the surface of the water than speed from point A to point B.

[TRBenj]

Perhaps I'm not understanding how zero off works. However, given that zero off is GPS based, I don't understand what difference it would make if you are running on a river. In fact, one of the advantages of a GPS system would seem to be that you wouldn't have to spend a bunch of time calibrating for current. Perhaps someone can enlighten me. BKH

Im guessing the confusion stems from what event the boat is pulling. If you are slaloming (in a course), then ZO would work great. When wakeboarding in a current (or anything else that you want speed over the water rather than speed over land) then ZO would skew the speed. I would think PP would be preferable in that situation.

[MHayes]

Perhaps I'm not understanding how zero off works. However, given that zero off is GPS based, I don't
understand what difference it would make if you are running on a river. In fact, one of the advantages of a GPS system would seem to be that you wouldn't have to spend a bunch of time calibrating for current. Perhaps someone can enlighten me. BKH

Here's an extreme example, but hopefully it will clarify your confusion. Say that the current of a river is 20mph; you could just tie a rope to a tree on the bank and wakeboard at 20mph. GPS would read 0 mph because the tree isn't moving (you can substitute boat for tree if you like). A paddlewheel, which measures speed over the water, would read 20mph.

[B-Unit]

GPS measure speed relative to the earth. When wakeboarding you would want speed relative to the water. I think the GPS just tells the speed controll how fast the boat is moving and the unit in the boat would control everything else, so should they be able to get the same accuracy with a paddle wheel?

[DanielC]

My personal choice, pitot tubes, and Airguide speedos.

[bkhallpass]

Thank you. I understand where this discussion was going now. BKH