Propping Chart and information.

You know the drill..

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urbnsr
Posts: 180
Joined: Tue Mar 29, 2016 6:54 pm
Location: Celina, Ohio

Re: Propping Chart and information.

#46 Post by urbnsr » Sun Jun 18, 2017 8:21 am

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/
Paul

scott2165
Posts: 5
Joined: Mon Apr 02, 2018 6:37 pm

Re: Propping Chart and information.

#47 Post by scott2165 » Thu Apr 05, 2018 7:08 am

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.

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guy48065
Posts: 475
Joined: Wed Jul 18, 2012 4:32 am
Location: Atlanta, MI

Re: Propping Chart and information.

#48 Post by guy48065 » Thu Jul 19, 2018 8:01 am

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)
Mark
1996 Sweetwater 180EX + Johnson 40
Rush Lake, Atlanta, MI

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curtiscapk
Posts: 4906
Joined: Mon Nov 10, 2008 8:31 am
Location: OP KS\Truman Lake

Re: Propping Chart and information.

#49 Post by curtiscapk » Thu Jul 19, 2018 9:18 am

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.
Craig and Paula
"THE FLOATER" rebuild Spring 2013
viewtopic.php?f=2&t=15328
94 Party Barge 24' 115 merc
Turning Point hustler 14 x 13 prop
22mph gps 3 people
12 F150
Overland Park Ks
Boat at Truman Lake, MO

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guy48065
Posts: 475
Joined: Wed Jul 18, 2012 4:32 am
Location: Atlanta, MI

Re: Propping Chart and information.

#50 Post by guy48065 » Fri Jul 20, 2018 7:13 am

Pretty expensive proposition if you don't have a marina that lends props to try before buy.
Mark
1996 Sweetwater 180EX + Johnson 40
Rush Lake, Atlanta, MI

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