GPS Speedometers

[UnorthodoxCreations]

I'm considering getting a GPS speedometer for my 2005 AR230. My main reason is to help with speed control when surfing. Since no one makes a speed control for this boat any more and finding a perfect pass used is like finding a unicorn, I need a way to know speed accurately. The stock speedometer fluctuates a fair amount until you get past 12-15mph or wakesurfing speeds. Are GPS speedometers more accurate in the 10 mph range or will I have the same problem?

 

[zipper]

Ours works accuratly thru the range. Ditched the dreamometer/paddle wheel for this. Problem is they don't sell them anymore.

 

[johhnyboat]

My Garmin Chartplotter GPS has a speedometer, I think it is very accurate. I have had the coast guard tell me that the GPS speedo is very accurate (as they were pulling me over for speeding

 

[Luc Lafreniere]

I have a GPS speedo on my Scarab. No issues and it works very well. All Scarabs have GPS speedos and I haven't seen anybody complain of any related issues. The only exception has been when someone decides to cover the GPS antenna with an object.. then there's an error code related to that.

I happen to work in airborne geophysics and literally process GPS data to highly accurate positioning. If anything, GPS is MORE precise at slower speeds. It becomes less accurate as you move faster. But it requires two consecutive points in a straight line to determine speed. So if you're going very slowly and zig zagging, then the speed can be off.

 

[jsg73]

The GPS speed on most fishing graphs is very accurate. It has to for consistent trolling.