Boat Speedo

[Gerry Mac]

This will help me thaw.



Can someone here enlighten me as to how a boat speedo functions. Obviously its got some kind of hose connection on it but from there I am lost. I just bought a new set of gauges for "Last Chance" my boat. It never had a speedo before. What else do I need to instal the gauge? I want one so I know how fast I'm pulling the grandsons. Also I am hoping it will help me get better use of the power trim. I am in no way a boating expert. I'm much better on wheels.

 

[Todd Z]

When your boat moves forward, water is drawn through a hole in the leading edge of the tube that is in the water. The water compresses the air trapped inside the inlet tube. The water to air pressure, which varies in relation to the boat's speed, actuates the needle movement in the speedometer indicating the speed of the boat. If the tube is damaged, clogged or tilted upward it may cause your speedometer to register inaccurately.

Todd Z

 

[Kevin Palmer]

There is also a style that is normally connected to a fish finder that is a little wheel like a paddle boat wheel. As the water passes under it, the wheels spins. In most cases, this style does not work when going slow as the water surrounds it. Once on plane, the wheel has water only on the bottom and the wheel spins.

 

[Dale Carter]

Gerry - dig the Mangelson bears at your house

 

[Fer Echegaray]

This is a granpa speedo... :lol::lol::lol::lol::lol:



<img src="http://www.barnyardboy.com/SPEEDO.jpg" width="300" height="400">

 

[Jake Levin]

Fer that's just wrong!

 

[Kevin Palmer]

It is wrong !!!

 

[Larry Phillips]

Theres also another one out there used on smaller boats, where there is a small spring loaded lever bolted to the rear of the boat that points down farther than the hull. As you're moving through the water, the pressure of the water rushing under the boat pushes the lever back and drives a cable that turns the speedometer.

 

[Gerry Mac]

I already have the speedo, its made by Faria. It has only a hose connection on the back, except of course for the light wiring. What kind of "gadget" do I buy now to get the message to the gauge from the water. (if tht makes sense at all)

 

[Mark B]

 

[Larry Phillips]

That's the exact one I was thinking of. (OK, so it's not a cable...) But Faria is what we've used on all our boats...

 

[Wes Davis]

If you want a true speedo that is not effected by wind, current or the speed of the boat (on plane or cruising) then you need to get a GPS with a MPH feature. Almost all GPS's have MPH now. Any GPS specifically manufactured for a boat will have MPH but some of the very small portable ones say for hiking may not.

 

[Gerry Mac]

Thank you all. I appreciate the help.

 

[Glenn Brown]

When you see your grandsons airborn, then you are going to fast!