calibrating speed

[bobberboy]

Last night I was on the lake and hit 30+mph with my 25hp Merc 4-stroke and 1448 boat - I'm still breaking the motor in and so wasn't running wide open. My speed is taken from the old-school paddle wheel on the boat and not GPS. Thirty plus seems too fast for this set-up. I don't have any GPS device to compare the speed on the locator to. Anyone know how to know if the reading is accurate. It doesn't really matter how fast I'm going , it's just interesting to know...

 

[Quackrstackr]

Those things are notoriously innaccurate and are usually on the high side.

I've seen some of them that were as much as 5 to 7 mph off.

About the only way to gauge it would be to ask your buddies if they have a handheld GPS and compare it against what the paddle wheel is giving you.

 

[Captain Ahab]

30 mph does not seem really fast for that boat and motor. My 25 hp on a 16' semi-V boat gets up to around 25 mph with one person on the boat - but a different prop could give more top end speed.

Any GPS will work - if you can borrow a Garmin unit from a car that will do teh trick, they run on batteries so you do not even have to screw around with wiring

 

[bobberboy]

Thanks. Do you guys think the inaccuracy of the paddle wheel varies. I've never had a speedo on a boat so I'm mostly curious. The only real use for me would be to have consistent trolling speeds. Otherwise it's not like I have to worry about getting a ticket or anything.

 

[crazymanme2]

I have speed on my graph & it works sometimes & sometimes not.I always carry a GPS if I want accurate speed & incase the fog comes in there's no problem finding my way back to the launch.