Moderated Discussion Areas
ContinuousWave: Small Boat Electrical
Pitot tube and speedometer
|Author||Topic: Pitot tube and speedometer|
posted 03-23-2008 05:48 PM ET (US)
With the use of GPS speed calculating units does any one have an argument in favor of maintaining a pitot tube speedometer on their Whalers?
I want to move my depth sounder transducer to the position the pitot tube is in and the thought stays in my mind not to put the pitot tube back on.
posted 03-23-2008 06:55 PM ET (US)
I never like the speedos anyway I would take it off. (they never worked right and got clog all the time) If your boat is already set up with the right/correct prop, and other than crossing the ocean (for navigation) do you really need to know your speed? And like you said you have it on your GPS...good luck
posted 03-23-2008 07:03 PM ET (US)
Yeah, there is no reason to keep it. I took mine out. In fact the GPS is much more accurate that a pitot tube (they tend to read a little high in the upper speed range, and then not at all a trolling or manuevering speeds).
The only thing that makes me cringe is the idea of drilling more holes in the transom.
If you re-use the exsisting holes, make sure they are water free. I usually stick a coton string, or cloth in the hole and tape it inplace. I come back a few hours later and see what I have.
posted 03-23-2008 09:39 PM ET (US)
If you deal with significant currents, pitot tube and paddle
wheel speedometers tell you speed THROUGH the water, while
the GPS tells you speed relative to the bottom. Ask yourself
if you care.
My depthfinder came with a paddlewheel. I hooked it up --
posted 03-24-2008 09:26 AM ET (US)
Some high-quality pitot-type speedometers can be quite accurate. Airplanes still use them to determine airspeed - like a boat airspeed is not quite as interesting as ground speed, but it's still important in ascertaining engine performance and fuel management.
If I had a boat in Maine up near the Canadian border where there are 20' tides and all kinds of inlets and outlets with incredible currents I would want to know both speed over water and speed over ground, but for your average boater in your average locale, I agree GPS-based ground speed is good enough.
posted 03-24-2008 11:51 AM ET (US)
Airspeed is esp. important to an airplane: it's what keeps
the plane flying. If you have a plane with a 60 knot stall
speed, a 40 knot tail wind, and an 80 knot ground speed, it's
falling out of the air because the airspeed is only 40 knots.
posted 03-24-2008 07:02 PM ET (US)
Thanks for your thoughts on the speedometer.
At this time I think I will remove the pitot tube.
posted 03-25-2008 06:02 PM ET (US)
My paddle wheel is used quite a bit when trolling, my paper charts have never blinked out and stated that the antenna signal is lost. John
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