$500+ to fill her up?
Nice! GPS won’t be accurate over a river current, so you’re probably right, she’s got more in her.
Wait why wouldn’t the GPS be accurate with river current?
Because it’s giving an effective land speed. If the current is driving you backyards 10 mph, but your boat is travelling 70 mph on that water, the GPS will tell you 60 mph.
Hmmmmm…interesting thought process there.
Care to elaborate?
@King (KCuv) and I are at Island Marine on Grand Island. Pros: it’s small, private, never busy, gated, inexpensive (I have a PWC though), gas seems cheaper than most places and the owner is always there helping out, answering questions, etc. Cons: current, waves & wind on the river can make for a difficult time docking. Cash only.
If you want to check it out, let me know and I’ll introduce you to the owner.
I’ve also spent a lot of time at Harbor Place, but that was years ago so my experience probably isn’t valid anymore.
GPS doesn’t differentiate between land and “sea” so whatever speed it’s providing (based on the accuracy of the system) would be correct. I’m not sure if you were trying to convey the concept of the current playing a factor in the speedometer on the boat itself.
Right, and the GPS speed won’t be the boats true top speed.
How fast can you run? 10 mph maybe? Lets use 10mph because it’s a nice round number. You run 10mph in a big parking lot with a GPS watch and it shows you moving 10mph. Perfect. Now I’m going to put you on a really big flatbed trailer and pull it at 5mph going straight east. You’re going to run the opposite direction the trailer is going. You’ll still be running at 10mph relative to the trailer, the fastest your legs and feet can carry you, but the GPS is going to say you’re going 5mph. It’s the same thing for the boat and it’s propeller moving against a current. The GPS speed is going to X mph less than how fast the boat is actually travelling through the X mph current.
Looking at it another way. If I put you on a treadmill and set the treadmill to 10mph how fast does the GPS say you’re running?
Oh, and the plane takes off.
Regardless of the current or the moving flatbed trailer, the distance covered over time is still accurate by the GPS reading. It’s not indicative of the boat or the runners top speed capability, but it is accurate if we are going on a point a to point b calculation, which is what mph is by definition.
True, but when people are bragging about top speed they want to know how fast it is and “a to b” distance isn’t really what they’re talking about.
Which is why a lot of ‘top speed runs’ use two runs done back to back in opposite directions, averaged together.
OK yes the GPS is accurate, but it’s not a good indicator of the speed of the boat RELATIVE TO THE WATER. That’s like running on treadmill and saying, “oh well since you didn’t actually go anywhere, then I guess you ran 0 miles”.
A paddle wheel speedometer measures speed relative to water you’re traveling on, so if there is a current, it’s taken into account. They can be VERY accurate if correctly calibrated as well. The paddle wheel speedometer on my boat is accurate and precise to 1/10th of a mph. Confirmed on a zero current waterway with GPS on my iPhone.
Geez, everything has got to be a damn argument on the internet.
I think you misunderstood what I was saying. Of course GPS doesn’t differentiate between land and sea, and I never meant to imply that. Jay’s treadmill analogy is pretty much it. If you were running 10 mph on a treadmill with a GPS, the GPS would tell you that you aren’t moving. River = Treadmill, Boat = you.
Take full speed measurement inside the break wall by the outer harbor. Then take full speed measurement going up stream under the Peace Bridge 
Or just take it where there is no current!
But does it take off on a treadmill?