"Bill Jeffrey" wrote ...

Newbie here. If I should be somewhere else, please let me know.

A couple years ago, I bought a pontoon boat. We chug around our lake with
it, and love it. I would like to add a speedometer. I've searched around,
and most boat speedometers cover a range of 0-60 mph, 0-70 mph, or even
0-80 mph. It is the NASCAR syndrome. This is completely useless on a
pontoon boat, of course, since top speed is 15-16 mph. So I'm looking for
a speedometer that covers 0-15 mph or 0-20 mph. Slow speed, in other
words. Best I've found so far is a unit that covers 0-35 mph, but the
scale is non-linear, and 15 mph is way down at the bottom of the scale.

Can anyone point me to a slow-speed speedometer, or a manufacturer or
distributor thereof?

Thanks in advance.

Bill

It seems that you have been looking at power boat speedometers since your
pontoon boat is, after all, a power boat. As pointed out elsewhere, you
need to look at sailboat speedometers as these will typically read in
fractions of a knot/mph ( half a knot is a huge advantage on a racing
sailboat). There are transom mounted paddle wheel sensors that could
probably be mounted on your pontoon boat. There are also some ultrasonic
sensors that shoot through the hull if you want to be high-tech. Probably
would not work if your hull is aluminum though.
You could buy a used Garmin GPS 48 on eBay for cheap and have speed and
location.

I loved this group! Tolerable levels of spam and trolls, and a lot of
good knowledge and help. Thank you, to all who replied.

To finish out the topic, yes, I was looking at pitot-tube units. And
being an engineer, I couldn't imagine that they could work well at
really low speed. But I was unaware of the paddle-wheel sailboat units,
so I thought I was stuck. I'll go back to the well (Google, in other
words) and see what I can find.

By the way, I really like the GPS idea. Although I own a more expensive
GPS unit (for geocaching)), it never occurred to me to get a cheap one
and just clip it to the dashboard. And two days ago, I came close to
Jack's scenario about Granny falling overboard. We started off down the
lake in the pontoon boat, with heavy hors d'oeuvres and light hearts.
After chugging along for about 10 miles, we turned around and started
for home. Unfortunately, heavy clouds blew in, and it was pitch dark
before we got back. I now appreciate the importance of having a few
waypoints pre-plotted - waypoints that are in the middle of the lake,
and will lead me home, even in the dark - and that will keep me off the
rocks.

So thanks, one and all.

Bill