Pontoon Boat & Deck Boat Forum

97 Harris with 3L I/O, I know there not known for there accuracy but where is the Pito tube on a toon like this,is it built into the outdrive?

Mercruiser Alpha drive? Yep. look at front of the bullet on the front of the L/U. There is a hole in a little notch about 3" above the bullet. Probably is clogged up. Use a 8" 1/8 inch drill bit with in vise grips. Spin the drill bit and clean out that hole. You'll probably get a little wood of crud out of it. Don't use a drill! I have seen many people drill through the cast, into the housing and that's all she writes for a huge bill.

Thanks gonna check it out tomorrow

Try blowing it with an airgun first.

Or... just replace your old gauge with a GPS speedo. It eliminates the need for any type of sensor or tubing to the transom and it's much more reliable. Just drop it in the dash, connect it to power and you're all set with reliable speed!

Have you tried the navionics app?

Basic mapping with contours, marinas etc on it, also has gps speedo

Its free try it

bansil wrote: ↑

Sun May 13, 2018 7:48 am

Have you tried the navionics app?

Basic mapping with contours, marinas etc on it, also has gps speedo

Its free try it

Navionics is a great app, highly accurate for depth contours. I pay $4.95 a year for mine for the Android version. I think you can try it free for two weeks. I like the bread crumbs feature. I can leave a trace of where I started from and find my back no matter what... ahem... condition the crew might be in or how dark it is.

And the GPS speedo is excellent. Pitot tubes are at best an estimate for speed

Which kinda brings me to a question. Which speed is most important?

If you're doing 10 mph against a 5 mph current according to pitot-based speedo ... a GPS speedo will show 5 mph (assuming both are accurate)

I saw this in airplanes too... where it's slightly more important as airspeed keeps you from falling out of the sky

100 knots indicated against a 40 knot headwind means you're only do 60 knots over ground.

Might be tomayto tomahto, but if you're in a canal system...residential area... and posted speed limit is 6 mph, what speed would be enforced?
If they open the locks down stream, you get current.

No, this is not a huge deal to me, but I'm curious what the answer might be.

more accurate way may be "the cooler way"

I know right?

So open cooler, count beer, you have 12 so,

you have 6 miles to go and speed limit is 6 mph (made it simpler math)

So 60 min/ 12 beers equals, you need to drink 1 beer in 5 minutes time, if you have 6 beers left and 20 minutes left then you either need to speed up or slow down the boat OR speed up or slow down the beer drinking



Or let your friend drive when you drink beer and he gets the ticket, unless you are an honest to goodness Captain...then

Good luck