What size prop for a pontoon?

[heavyduty413]

I've got a 18 ft. pontoon with a 2000 40hp elpto 2cyl engine. What's the best size prop to run on it to get the most speed and power? I use it for fishing carrying 3-4 men, 2 batteries and fishing supplies.

 

[steelespike]

Re: What size prop for a pontoon?

What is the present prop?What is the max rpm and speed.Its difficult to select the best prop without a baseline performance.My guess is a 11" pitch.
perhaps a 9 if 4 men and gear is the norm.You shouldn't make any changes without a tach

 

[heavyduty413]

Re: What size prop for a pontoon?

Tht WOT is 5500 and I don't have a speedometer. The one on it is a 12 1/2 x 8, but it doesn't seem to push it good.

 

[steelespike]

Re: What size prop for a pontoon?

Rpm is good but without speed can't tell if it is really doing its job.Could you borrow a GPS or perhaps take a friend with one for a ride?Sometimes a 4 blade will do a better job.
Under ideal conditions boat could do 18-21 mph.depending on size of the logs, weight,weight distribution, motor trim,setup etc.