How accurate?

**Crappie Buster** · 03-29-2010, 04:48 PM

How accurate or handheld GPS speeds on water. I tried running my new to me boat with a handheld GPS to see what she'd run. It doesn't seem very accurate to me. I had 3D position fix and at 3000 RPM's I was running 30 mph. That seemed about right. Then when I trimmed her out to 5500 RPM's I wasn't doing but 40 mph. Just don't seem right to me. I've had a buddy with me that has a boat that will run 52 on GPS and he says at WOT my boats moving just as fast if not faster. It's a 18 foot fiberglass bass tracker with a 150 Mercury XR4.

Now, I have read numerous reviews on the same boat and other 18 ft boats with 150's and everybody says they get between 55-65 depending on several factors....

How could I possibly be 20 mph slower? And it just seems like I'm moving along faster? What's going on?

**feelay** · 03-29-2010, 07:32 PM

Why does it matter? I find no need to know the speed over 3 MPH (trolling speeds).

**wilbur** · 03-29-2010, 07:39 PM

A crappie will never catch the jig at 55mph

**Johnsfishin** · 03-29-2010, 07:53 PM

55-65 degrees not mph. I crank up my 40# troller and let her eat gets me where i need to go!

**sparkie51** · 03-30-2010, 08:59 AM

Take with you in your car or truck and match it to the speed your going. Mine is right on all the way up to 70mph, don't drive over that.

**badbrad** · 03-30-2010, 09:20 AM

I've got an 18ft boat with a 150 Johnson @ WOT, 5500 RPM's mine will run out around 62 MPH. I've checked it with a handheld GPS and my graph and the speeds are consistent. Probably need to check the gps out, from what you describe your probably running faster than 40. If not, then you've got something going on with your boat.

**Crappie Buster** · 03-30-2010, 09:43 AM

Originally Posted by feelay

Why does it matter? I find no need to know the speed over 3 MPH (trolling speeds).

It don't really matter, just curious. I'm willing to bet that I do less running than all of yall. For the most part I don't even change spots while fishing and normally I fish from within sight of the dock....and catch fish doing it:D

There isn't a real good reason, but it just bugs me that I'm not getting an accurate reading on speed. I can't run it like that often anyway cause of gas prices :p

**Crappie Buster** · 03-30-2010, 09:45 AM

Originally Posted by badbrad

I've got an 18ft boat with a 150 Johnson @ WOT, 5500 RPM's mine will run out around 62 MPH. I've checked it with a handheld GPS and my graph and the speeds are consistent. Probably need to check the gps out, from what you describe your probably running faster than 40. If not, then you've got something going on with your boat.

That's what I'm talking about.... my boat should be running right up there with yours, not 20 mph slower. I'm pretty sure something is happening with the GPS. There is definitely more than a 10 mph increase between 3000 RPM and 5500 RPMs.

**Kman** · 03-31-2010, 09:04 AM

are you sure your GPS isnt set on Knots instead of MPH? Happened to me once!:o

Very rare to see one not be accurate though. Try it in the car against your speedometer like someone else said. Then you'll know fo sho.

**Cricket Chunker** · 03-31-2010, 10:51 PM

also make sure your GPS is showing real time COG and not average speed. It makes a huge difference. First time I used my hand held it was showing average which was way off the actual real time speed.

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