Propeller pitch

[natedog337]

What's the rpm and speed difference between a 4 blade 13 pitch and a 3 blade 15 pitch prop

 

[QC]

Re: Propeller pitch

You probably need to read up a little more on props. Check the stickies above. I could say that the RPM difference would be about the same, but not enough info for that. Usually we say one inch less for four blades vs 3 to be at the same RPM. No way to judge speed with out a lot more info. Boat, engine/motor combo. Speed and RPM today and with which prop? etc. etc. Get us some more info, and we'll help best we can. Mo info = mo betta . . .

 

[natedog337]

Re: Propeller pitch

You probably need to read up a little more on props. Check the stickies above. I could say that the RPM difference would be about the same, but not enough info for that. Usually we say one inch less for four blades vs 3 to be at the same RPM. No way to judge speed with out a lot more info. Boat, engine/motor combo. Speed and RPM today and with which prop? etc. etc. Get us some more info, and we'll help best we can. Mo info = mo betta . . .

Thx for the info

I have a 26 foot pontoon getting 27mph with Solas 13pitch 4 blade prop
Yamaha f115 on the back..

 

[QC]

Re: Propeller pitch

RPM? Speed is GPS?

 

[natedog337]

Re: Propeller pitch

RPM? Speed is GPS?

Getting 27mph at 5900 rpm. My engine is rated for wot 5000-6000

 

[natedog337]

Re: Propeller pitch

Getting 27mph at 5900 rpm. My engine is rated for wot 5000-6000

And yes speed is gps

Thx again

 

[QC]

Re: Propeller pitch

Ok, based on what I am seeing, with the 3 blade and 15 you may bring RPM down towards 5500 and could possibly reach 30, but that is assuming a lot. Being the middle of the WOT range is good, especially if you are running typical loads and your hole shot is OK. Pontoons are unique as well, and I don't have much experience. Why do you want to change props in the first place? What do you want to achieve. Can you elaborate?

 

[natedog337]

Re: Propeller pitch

Ok, based on what I am seeing, with the 3 blade and 15 you may bring RPM down towards 5500 and could possibly reach 30, but that is assuming a lot. Being the middle of the WOT range is good, especially if you are running typical loads and your hole shot is OK. Pontoons are unique as well, and I don't have much experience. Why do you want to change props in the first place? What do you want to achieve. Can you elaborate?

To be honest I'd like to have an extra propeller inboard incase of emergency and figured I could try to get a little more speed out of it

 

[QC]

Re: Propeller pitch

Then you should try it. One or the other becomes the spare, and I think you are going the right way, especially with a four stroke. As long as the acceleration is good now, became what you plan will cut into acceleration a little. Props are really hard to guess at, although someone with some specific pontoon experience might be more helpful.

 

[steelespike]

Re: Propeller pitch

The motor max rpm is 6,000 your at 5900 and 27 mph on a 26 footer with your present prop.That seems very good to me.
You could try the same prop in stainless, if it doesn't break the bank.And use the aluminum as a spare.

 

[QC]

Re: Propeller pitch

Is 20% slip reasonable with a 'toon, spike?