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Re: Propping Chart and information.

Posted: Sun Jun 18, 2017 8:21 am
by urbnsr
Here is another calculator. I have used this a couple of times and am satisfied. You can search by motor + boat length or by motor + pitch/RPM.

https://www.miwheel.com/outboard-propel ... -analysis/


You can contact them for advice, too.

https://www.miwheel.com/contact/

Re: Propping Chart and information.

Posted: Thu Apr 05, 2018 7:08 am
by scott2165
I’ve had a tough time searching for data so I’ll add mine here in hopes in will help someone.

2009 Bentley 240 Cruise with 2016 Mercury 115 4 stroke.

It can with a stainless 3 blade 13x21 prop. Top speed 18mph at 4400 WOT.

I changed to a 3 blade 13.5x15. Top speed 26 at 6000WOT but also easily hit rev limiter.

I just ordered a 13.25x17 3 blade. I’ll post results when I test next week. I anticipate not hitting limiter and being right around 5800 WOT.

Re: Propping Chart and information.

Posted: Thu Jul 19, 2018 8:01 am
by guy48065
I just read this topic beginning to end and it raises a question: In the first posts there is much weight given to reducing prop slip, then several posts questioning if low slip is even possible on a pontoon that plows rather than planes. By the end there's no mention at all of prop slip.
I've looked at several prop selection guides online (mostly interactive calculators) and almost none ask the boat weight or hull type.

So what's important and what isn't when trying to select a starting point for propping a pontoon? Have we learned anything or is it just trial and error?

(Of the 2 calculators I tried with my boat/motor info I got 2 very different recommendations: 12.5x13 3-blade & 11.5x10 4-blade. On another calculator I get very different suggestions for my 18-foot boat depending on whether I select the "15-18 foot" or "18 foot or more" options. This doesn't appear to be very scientific)

Re: Propping Chart and information.

Posted: Thu Jul 19, 2018 9:18 am
by curtiscapk
Props are never a perfect science! All trial and error until you find that right one that hits your suggested max RPM's at WOT for you're motor.

Re: Propping Chart and information.

Posted: Fri Jul 20, 2018 7:13 am
by guy48065
Pretty expensive proposition if you don't have a marina that lends props to try before buy.

Re: Propping Chart and information.

Posted: Sun Jul 19, 2020 3:55 am
by bigi
I have a 2014 Harris Cruisers 200 with Mercury 50 EFI BigFoot. AT WOT using 4 blade 13 7/8" x 13 P with 2 people on board, I get 4100 rpm at 18.6 mph per Gps. Any suggestions for new prop?

Re: Propping Chart and information.

Posted: Mon Nov 01, 2021 6:18 pm
by MattGent
6 years on and its time to repower my little pontoon for more speed...want to pull kids on tubes/kneeboard/skis or whatever.

I've bought an F70 to replace the DF30 and pulled similar data as last time.

Image

The boat runs ~17mph with the DF30; hoping/expecting mid-20s with the F70. All of the boats above are longer and heavier than mine. Most run 20-22mph top speed; the two Veranda boats run about 25.

All the other boats run 20-25% slip; the two Veranda boats run 7% at WOT. One of the Verandas uses a 9" pitch "Pontoon Performance" stainless prop; the other runs a 13" Aluminum. Yet they have the same engine and nearly the same performance. I actually think the data for both Veranda boats, on the Yamaha bulletins, is bullshit. I've never seen another pontoon (excluding the super fast ones) anywhere near 7% slip.

I think I'll start around 13" pitch, hoping for 25-26mph at 20-22% slip. Just need to find the right model. Maybe this https://www.overtons.com/solas-3-blade- ... 34987.html

Re: Propping Chart and information.

Posted: Thu Nov 04, 2021 2:29 am
by steve1313
I gotta agree with you.......No way the Veranda models are that low. Not unless the toons are coated with some kind of super secret anti-friction compound and measurements were taken as the boat was going over a waterfall.

Re: Propping Chart and information.

Posted: Thu Nov 25, 2021 11:52 pm
by MattGent
Working thru break-in on the F70. Initial results are 26mph solo/light with the 13” SS Solas, plenty for recreational tubing and skiing. Boat planes quickly but doesn’t continue to lift out of the water, drag picks up pretty quick. Happy with it for now. More data later.