2015 Sweetwater 240 SLR Tritoon w/Yamaha F200 Motor

[JB NC]

Hey - Recently bought the above from a friend who moved out of town. I've been on it previously doing 35mph, on my maiden voyage under my ownership however, she's only pulling 25. Things to note:

- The bottom is absolutely filthy (winter sat in lake water)
- It has a replacement prop recently (yet to get my hands on the old one to determine if its the same pitch, will have it soon)
- 25" toons I believe

She pops up on the plane nicely around 15, accelerates up to 25 reasonably enough, balancing trim as I go etc.... then that's all she has, rpms around 5300ish maybe, WOT. Trimming in at that speed doesn't massively slow it - then engine just works harder (you can hear that hollow intake type noise), trimming out results in more rpms, but no massive speed gain - assume it's cavitating slightly.

Can dirty toons really knock 10mph off the speed?
Trying to understand if it's the filth, possible wrong prop or engine issue.

I read forums hearing of easy 40+mph speed from seemingly similar boats with like 150hp motors... I was honestly expecting this would pull 40 in the right conditions.

Appreciated in advance!

 

[Scott Danforth]

yes, dirty toon logs will knock out your top end

dont count on 40mph unless you have a 3rd log and lifting strakes.

 

[JB NC]

Thanks. She is a tritoon with lifting strakes on the front.
Fingers crossed the clean sorts it

 

[ahicks]

You might want to check to see what max rpm should be. I know 5300 would be high for a Honda for instance. Unless you really need that max low end grunt you'll get with a prop turning max rpm, I'd stay conservative. Noteworthy, is that the Honda's start sounding pretty busy when turning max rated rpm. They sound MUCH better, and are occasionally faster, if propped about 4-500 rpm low.

Congrats on the new boat!

 

[JB NC]

Thanks - yes, I will research the motor and get the stats.

 

[HotTommy]

JB NC -
In order to do an apples-to-apples comparison, there are several things to consider. First was the boat carrying the same load both times? Carrying 500 pounds of additional fuel, people and gear will have an effect. Second, was the wind strong on either day? Pontoon boats catch a lot of wind, so a tailwind can help a lot while a headwind hurts. Lastly, are you using GPS MPH or water based speedometer? If using GPS, know that water currents (if present) can have an effect like a headwind/tailwiind. If you were on the wrong side of all these conditions AND you have a different prop and additional drag from dirty logs, I can see how you could drop from 40 to 30.

 

[ahicks]

^^^ yup! ^^^

 

[JB NC]

Thinks guys, will update back once i have news