Lets talk pontoon speed- NEW RESULTS

00247

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Sep 7, 2010
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I upgraded to a 2004 Playcraft 24' pontoon with a 135 Honda. We had it out on it's maiden voyage and found it to be a great pontoon. BUT. While the acceleration is great the wot speed is not. The best I could do was 22 on gps at 5200 rpm. Adjusting the trim made no difference in speed and the rpm would only rise to 5300. The facts: It is a tritoon with a lined bottom and lifting strakes (4). Weight according to Playcraft's site is 2600. 2 adults, 3 kids, and the usuall stuff. Smooth conditions with minimal wind. Bimini top up or down, no difference. Engine freshly serviced. Prop is a 3 blade SS 14 3/4 x 16.

My guess is to drop the pitch to 14 with a slight increase in diameter but will that give much more top speed? Your thoughts? Thanks
 

Bamaman1

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May 15, 2011
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

I would have thought that you'd be getting more than 22 mph out of a tritoon with 135 hp and lifting strakes. Your RPM's appear right, which would indicate your prop is okay. Most pontoons run a pitch lesser than 16, however a 13 pitch prop will slow you down (on paper.) Is your motor sitting too deep in the water???

You may be the product of a relatively heavy weight engine that doesn't have the horses to get a "heavy" pontoon up on a plane. I have read that lifting strakes require more than a minimal amount of horsepower--and they'll then take off when the lifting takes effect. Wouldn't your boat be great with a 250 hp SHO Yamaha--for about $17K?

You might need to contact a prop shop to see what they suggest. Some boat dealers are better than other dealers at setting up boats, and they may can point in a direction.
 

lmuss53

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Sep 9, 2008
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

Are the tubes clean? If the boat lives in the water crud on the tubes will slow you down. I would think there was 8 or 10 mph to be had there somewhere. I would probably go to about a 13 on the prop for your next try. With your usual load you want to run the motor at the high side of the range. I think the 4 stroke is OK out to 6000 rpm isn't it?

Playcraft is known for having the performance package figured out on pontoons, and I have seen claims of 21 and 22 foot boats with 115's hitting 28 and 32 MPH. I think your boat should fall in that range somewhere.
 

lakegeorge

Senior Chief Petty Officer
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Mar 19, 2002
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

Go to the web and typi in... boat tests... you will find many different sites that have tested pontoons and get some idea of what yours should do.
You should be getting a lot more speed that that. Did you check the logs for water?
5,200 rpm's is a little low.
 

rrhodes

Chief Petty Officer
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Jun 24, 2008
Messages
636
Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

+1 On the motor being mounted too low. I have a 25' TriToon with a 115hp Honda 4 stroke which is a heavy motor and Lightly loaded with 2 adults I get about 28mph

If trimming up does not make a difference then I would say you need to raise the motor. Your RPM's should be 6000 I think.. Double check that with your manual. I would think a 15p trimmed right would get you about 32mph.
 

00247

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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

Thank you for the replies. You raise some possible issues. About motor depth. The anticavitation plate is about 9" below the water line and about even with the trailing edge of the center 'toon with the center of the prop being about 17" below. Is that about right? The motor is in the lowest position. I have not had any cavitation even during full power sharp turns. In fact, I never noticed any cavitation even when trimmed up. I will try to add a picture. There is some crud underneath. The out side of the side 'toons have been cleaned but there is crud on the insides and on all of the center 'toon. I would imagine the crud under the lifting strakes would cause a lot of drag in that high pressure area. I will address that. The rig runs out nice and accelerates great but seems to run up against a wall at 22 MPH. Maybe the crud and prop are the wall. I would like to see 5800 RPM and thought I would get 28-32 MPH.

Wouldn't your boat be great with a 250 hp SHO Yamaha--for about $17K? Oh man! Don't get me started. If only...

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rrhodes

Chief Petty Officer
Joined
Jun 24, 2008
Messages
636
Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

Here are a couple of pics of my 115

rear.jpg

side.jpg
 

00247

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Sep 7, 2010
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

I was under the pontoon with the pressure washer and found that the crud was not as bad as it looked. I doubt it was robbing much speed. I added another picture from the rear showing motor height. It wouldn't upload before. rrhodes, your motor looks lower than mine. I'm not sure where my missing 8 MPH is.





Uploaded with ImageShack.us
 
Joined
Jun 11, 2011
Messages
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

FWIW =

My 26' tritoon with older 175 2stroke got 38 mph at 5500 with some moss and 40 gallons of gas
and 6 passengers.

With 225 hpdi got 43mph with similar conditions. Using a 3 blade 19 pitch Ballistic prop. Lots of pull out of the hole.

Forgot one detail. I added a power jackplate to get lower in the water. Your motor appears to me to not be deep enough in the water.
 

00247

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Sep 7, 2010
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

It finally quit raining and I got the Playcraft out on the water. The three toons got a good cleaning and the first run with the 14 3/4x 16 ss prop yielded 26 MPH at the same 5200-5300 RPM. That was a 4 mph result from cleaning the bottom of the pontoon. I did have one less kid on the run but I don't consider that relevant. The Playcraft can really get up on plane with the "RAC-R-Fins" lifting strakes. I then switched to a 15x15 aluminum Rubbex prop that the Honda dealer told me to try out to see if it would be in the right direction. I wanted to try a 15.5x13 aluminum but he did not have one in stock and did not want to order not knowing the result. The results were surprising. The 15x15 would do 28 MPH but at 5100 RPM. The thought was diameter would be insignificant, the one inch less pitch would give 200 RPM, and the aluminum would flex enough to give another 100 RPM. WRONG. I had an opportunity to talk to Mark at North American Prop and he said there is less difference between ss and aluminum props nowadays. Better castings and aggressive blades have made aluminums much better. What are your opinions of trying the 15.5x13 Solas? The Honda book recommends the 16x13 but that only has 1/8" clearance to the cavitation plate which seems to close to me. North American Prop says that is no problem. So, 15.5x13 or 16x13? Chime in boys!
 

Silvertip

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Sep 22, 2003
Messages
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Re: Lets talk pontoon speed

Re: Lets talk pontoon speed

There is a misconception that dropping pitch ALWAYS results in loss of speed. The reason you can't get the engine up on its power band is because there is TOO MUCH pitch and the engine is lugging (which is not good for the engine by the way and can lead to "making oil" due to fuel dilution.) Try less pitch and you will find the engine now has the power to get "over the hump" so to speak and you will see speed increase. How much that increase is can only be determined by trial and error -- and ALWAYS do your testing with what you consider an average load. Prop it for a heavy load and you will over rev at light loading. Prop it for light loading and you will lug the engine with a heavy load. Playing with engine height on a pontoon can provide a benefit but keep in mind the engine operates in very turbulent water so ventilation can happen if mounted too high. Your setup looks ok.
 
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