Pontoon prop for speed

[old islander]

Hello all, I have a friend that has a 2012 Tahoe pontoon with a 2012 Yamaha 90HP 4 stroke on it. His prop is the stock Yamaha 13 3/8 x 13 three blade aluminum that came on the boat. The prop is not a full round blade prop. It has a half round, half straight design { I have heard them called chopper props?** Anyway, he uses the boat for fishing and trolling for stripers at about 2mph at 600 rpm. Right now he runs wide open at 19-21mph at 6000rpm. He's looking for a bit more top end speed. Is there a better pitch he could use to get a little more speed out of this barge? or a better blade design that would get this thing moving a little faster from spot to spot? Any and all advice welcomed.

 

[steelespike]

Pontoon speeds are all over the place for no apparent reason.
Boats I checked ranged from 3600 total weight to about 2400.
the 2400 lb made only 24.2 with a 14" painted stainless prop at 5800 rpm.
A 3000 lb with a 14" performance series made 29 @ 5900
You should check the Yamaha Performance bulletins.
Typical prop is a 14" Check out the Pontoon series props.
Gps speed is best to evaluate your performance.
Don't assume because it's relatively new that everything was set up right.
Check that the throttle opens all the way.
Be sure it is in excellent tune.
Is the speed with a light load?
A lightly loadfed wot rpm and gps speed would help tell.
It does appear that the typical; 90 runs a 14" prop.
Though there are exceptions.