Pontoon Boat & Deck Boat Forum

I know this has been discussed so many times, but here we go again:

Looking to optimize my prop on the new to me pontoon. The current prop is in okay shape (a few scuffs, no major dings or chunks out) but I feel from reading on here and looking at the Yamaha Service Bulletins that I could get more speed.

CURRENT SPECS:
13 x 15 4-blade, aluminum
2004 Tahoe Blue Ridge 22’
Twin Pontoons
Weight 1460 lbs
2004 Yamaha F115 TLRC
Weight 414 lbs

1000 RPM 2.7MPH
2000 RPM 6.0 MPH
3000 RPM 10.3 MPH
4000 RPM 11.7 MPH
5000 RPM 19.7MPH

WOT 5300 RPM

Speed was recorded with GPS, tank had about 18-20 gallons of gas in it, four adults, on a wide river at about slack tide. Speed going up and down river was very similar. Very small waves. Not sure of hole position of motor. I played with the trim (which I'll admit I'm new to) and got very little increase in speed with different trim.

I know it's hard to compare apples to oranges, but on all the Yamaha Performance Bulletins, the WOT is higher, and the top speed is significantly higher. It also seems like the diameter on this prop is on the small size.

Did not get a chance to see if prop blew-out on corners. I should really get it out on a lake and test, but those are far away in Maryland.

I don't intend to do much towing beyond my small nephews on a tube or banana.

Thanks for the help!

Todd

Plain pontoons or do you have lifting strakes ?

Does seem slow.... but what would it spin up to if you were by yourself (lighter load)

If you drop down a prop, you might get some more rpms and speed out of her.....

With no lifting strakes, there is a lot of drag on those tubes.....

Evanyj350 wrote:Plain pontoons or do you have lifting strakes ?

Does seem slow.... but what would it spin up to if you were by yourself (lighter load)

If you drop down a prop, you might get some more rpms and speed out of her.....

With no lifting strakes, there is a lot of drag on those tubes.....

Forgot to mention, no lifting strakes.

I just spun your numbers and you are about 50% slip, with your current prop. First, I have to ask, are your pontoons clean? That will kill your speed. Next, from running more numbers, if you ran a 14X12 or 13 3 blade Round eared prop and we could get slip to 30% or lower and RPM's up to 5500, I think you'll see 26 to 28mph. I'm not too good at stock Yamaha props (i'll be learning starting Friday) but I think a Pontoon Series, Solas or a Merc Enertia with a Yamaha hub kit might get you in the right direction for a good start.

another thing you need to look at is motor height
is there room to raise the motor a hole or two
if the motor is too deep you will be slow and have lower RPM's

it is easy to raise motor with a floor jack
That prop on you boat should be close for that motor

Good luck

Mike

Bryden24shp wrote:I just spun your numbers and you are about 50% slip, with your current prop. First, I have to ask, are your pontoons clean? That will kill your speed. Next, from running more numbers, if you ran a 14X12 or 13 3 blade Round eared prop and we could get slip to 30% or lower and RPM's up to 5500, I think you'll see 26 to 28mph. I'm not too good at stock Yamaha props (i'll be learning starting Friday) but I think a Pontoon Series, Solas or a Merc Enertia with a Yamaha hub kit might get you in the right direction for a good start.

Bryden-
Thanks for the info. The toons do need a good cleaning. The previous owner had the tubes painted with anti-fouling paint a season or two ago and it's starting to chip. I don't intend to keep the boat in the water so need to get that off at some point (yet another topic of research).

So you're saying a 14x12 or 14x13 would be a good starting point. Not that I question you, but what's the rational on 3-blade vs 4-blade (I've heard people come down on both sides of the subject).

If you do learn any more the coming week on yamaha props I'd love to hear it.

Thanks again so much for the help.

Todd

crookedlaker wrote:another thing you need to look at is motor height
is there room to raise the motor a hole or two
if the motor is too deep you will be slow and have lower RPM's

it is easy to raise motor with a floor jack
That prop on you boat should be close for that motor

Good luck

Mike

Mike-I need to take a look at that and post some pics. Three stout men, a floor jack, and a 6-pack may be necessary in my case.

Thanks
Todd

ToddS wrote:

crookedlaker wrote:another thing you need to look at is motor height
is there room to raise the motor a hole or two
if the motor is too deep you will be slow and have lower RPM's

it is easy to raise motor with a floor jack
That prop on you boat should be close for that motor

Good luck

Mike

Mike-I need to take a look at that and post some pics. Three stout men, a floor jack, and a 6-pack may be necessary in my case.

Thanks
Todd

6 pack sounds awfully optimistic. you better re check those #,s

I have ran 3 and 4 bladed props on my pontoon boats. I always get lower slip numbers with the big eared 3 blades over 4 blades. I talked to Ken at Prop Gods about it a while back after I had terrible luck with a Typhoon 4 blade and we think that the reason is we have more space between the blades on the 3 bladed props to have enough water to grab. the 4 blades, while have more blade surface, are less capable to grab clean water, because the blades are closer to each other, so they slip more. The hulls on pontoon boats are harder to push than a v bottom runabout, which a 4 bladed prop may work great on. On a pontoon the prop works harder to grab the water around it. My 250 Etec, got the best slip numbers with a Rebel. My Verado, got the best numbers with Enertia's and Mirage Plus's. This is what I found on my 2 last pontoon boats, others have great luck with 4 blades. This new Manitou/Yamaha combination may like a 4 blade better. I'll play with it when I get it. I'm gonna start out with a 17, I think I'll burn the hell out of it, but it will be a good starting place.

So after getting sidetracked with other projects, I'm back at the prop. Ken at prop gods recommended I go with a 13 5/8 x 13 3-blade if I go aluminum. I'm going this way for now as we have a lot of shallows in the river and bay.

I know that the shape of the blades, etc. makes a big difference. It looks like the larger blade size is preferable for pontoon boats.


Any suggestions for specific manufacturers? I can't find a whole lot of info on the cupping or rake from product descriptions. Also, I see props that are 13 3/4 or 13 4/5 (that's a new one on me). Would this minor diameter distance really matter much?



Thanks
Todd

I'm the other way around, I couldn't get any 3 blade to grab more than OK on my intermediate case engine, including 3 blade stainless large ear "pontoon" props. I've had great luck with 4 blades though . Each boat/toon is different! My best performing prop,except top speed, is a cheap 110$ Solas Amita 4 blade.

I have a 22ft with a merc 60hp by my self & gps I can get 18mph no wind with bimmi up