TrI toon poor top speed

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Aug 11, 2017
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1) Performance issue you are trying to correct.
Poor top speed.
2) Current prop manufacturer, model, aluminum or stainless as a minimum.
Solas 4 blade 14.74 x 15p aluminum.
3) Current prop diameter and pitch (required).
14.75 x 15p.
4) Wide open throttle RPM and speed with an average load (very helpful)
5800 rpm and 22 mph gps with one person no extra baggage.
5) Engine/drive make, model, year, and HP
05 honda 150 outboard, 2.14 gear ratio.
6) Boat make model, year, length and weight
05 bentley 243 tritoon around 2500 lbs

Looking for some help on a new prop selection.
Boat is used to cruise the lake and pull tubes.
Motor starts right up just looking at the key, out the hole the boat jumps right up and plans out quickly.
Top speed is just slow, will cavatate if turned hard.
Motor is on the next to the top hole so it can go up but don't know if that will help ? Not much difference from 4500 rpms to wot. Played with online pitch slip and said it was 40 % ? What should I try to get the speed up ?
 

jimmbo

Supreme Mariner
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May 24, 2004
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12,944
What is the WOT range for your engine?
40% slip sounds a little high, even for a pontoon. Are you trimming the engine out as the speed increases? Move the wife, kids, Mother-in-law to the back of the boat, or better still, leave them on shore. Mistresses and Girlfriends can remain aboard.

Are the tubes dry, or have they taken on water?
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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how deep is the motor? you may need to go down if your ventilating in the turns.
 
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Aug 11, 2017
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Speed given was with me alone on the boat, no wife or mistresses on board at the time. No wind, calm lake. The motor can go down one more hole and that's it. Tubes are dry. No lifting stakes . 50 mph would be outstandin to hit ( jokes ) but really 22 seems way slow for this boat.
 

ahicks

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Sep 16, 2013
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If it's cavitating only when turned hard, and you don't plan on doing that a lot (thinking tubers here?) your engine is likely set for optimum - by standard twin tube pontoon standards that I know anyway. I have to admit to no tri-toon experience. Surprised to hear no lifting strakes on a boat like that. Without them you may not be getting much more than you have. You have more power for sure, but it sounds like you also have more hull in the water.

You're already turning max rpm. You can't get much closer than that. So thinking with engine height already close, if you gain anything it will be due to increased prop efficiency at higher speed. The only thing I can think of is to try a 3 blade prop. I'd stay with aluminum, as the boat is just not going to go fast enough to take advantage of a stainless - without even considering they're 2-4 times as much money. I'd also make sure the prop is cupped.

Do you have a local shop everyone in the area uses for prop repair? It's worth asking around if you aren't sure, as somebody like that may have something used that you can try to see what happens when going 3 blade. At best, that's going to be an educated guess.

Best of luck! -Al
 

Faztbullet

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Mar 2, 2008
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15,589
No lifting stakes . 50 mph would be outstandin to hit ( jokes ) but really 22 seems way slow for this boat.

40 mph is max with a 150.... Need to check your load and motor height

Test Result Highlights
  • Top speed for the Bentley 243 Cruise Tritube (2006-) is 39.8 mph (64.1 kph), burning 14.5 gallons per hour (gph) or 54.88 liters per hour (lph).
  • Best cruise for the Bentley 243 Cruise Tritube (2006-) is 15.1 mph (24.3 kph), and the boat gets 5.59 miles per gallon (mpg
 

gm280

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Jun 26, 2011
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With a tri-toon, you have a heck of a lot of drag in the water. I also think 22 mph is about it. You can't make a tri-toon into a Bass boat. The designs dictate how fast it will go. Drag is your biggest problem. JMHO
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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to get to 50hp, your going to need a lot more than 150hp. more like 350hp. remember, it takes 900hp to get a tri-toon to 108mph.
 

ahicks

Captain
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Sep 16, 2013
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I did some digging, and 2 things stand out for me. First, strakes were an option. The ONLY way you're going to see speeds comparable to what some others are claiming (40+mph) is if you have those lift strakes that lift the boat up out of the water - in my mind anyway. Second, the '05 boat uses a conventional engine pod in back of a shortened center tube. This can't possibly be as efficient as other boats with a transom built in to the back of a full length tube.

Bottom line, you may be able to improve on the 22mph, but you're not going to see a lot more than that.
 
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Did some checking and your right ahicks, the middle tube is about 3 feet shorter than the outside ones, it's also flat on the bottom " to aid in lift ". The motor is on a small v shaped pod . I have ordered a new tach as the one in it is sticking from time to time. I also called the previous owner who said he had a 15 x 15 three blade on at one time and it ran 28 he thinks.
He put the new prop on because the other was bad about blowing out ? His words.
 

ahicks

Captain
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Sep 16, 2013
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"Blowing out" = cavitating. That issue can be an absolute pain in the butt when pulling tubers - happens most often when turning hard and when accelerating initially, prior to the boat and the tuber getting "on top".

2 thoughts regarding that. First, prop design will often play into how easily a prop "blows out". Cupped designs are usually more resistant. There are also props specially designed for big "draggy" boats like pontoons.

Then, dropping the engine so it runs a little deeper in the water is a well known cure. Engine mounting height is nearly always a "best guess" scenario on the first pass, and may take a couple of tries to get it right. Too low, kills top speed, too high offers little "blow out" resistance.

Bottom line, looking for that "tweak" or "tweaks" that gives the best all around performance for YOUR needs, will require some patience and a willingness to mess around with those variables.

Last thought, I didn't notice the flat bottom on the center tube. That in mind, there may be a point/performance level or set of conditions where this boat might get up on "step" where it finally breaks free and picks up some speed, making it worth messing around to see if that's achievable. I'd be pretty tempted for sure. Keeping the boat as light as possible (gear carried aboard at minimum), will work to your advantage. Carrying around 40 gallons of gas (likely a month's supply?) would be something to avoid as well.

Best of luck! -Al
 

jkust

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Aug 2, 2008
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Just from the perspective of the fact that pontoons have taken over my large lake to the point where sometimes I can be the only bowrider on the lake out of dozens that I pass. Most are quite a bit newer than 05 since the trend hit in the last 5 or so years but your speed is about what people are getting with 24 foot pontoons not tritoons and with 115's not 150's. Most of the tritoons either have a minimum of 250hp on them if a single engine with some twin 300's and a few twin 150's tooling around. My thinking is you are a few MHP's shy of what I'd hope for with only a 150hp. I can't count the number of times that my tritoon and pontoon friends are disappointed with their top speeds because on a large lake, it takes a long time to get anywhere and get home when the need arises. The trend is to get rid of your fishing boat and your bowrider and condense into one pontoon or tritoon to get rid of a boat lift, an insurance policy and a garage space. It is like a slow motion obstacle course most days.
 
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Aug 11, 2017
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Yesterday I got off work earlier than planned and the kids where out of town so I had some free boat time.
I installed the new tac and did a quick run. 21 mph at 5500 rpm. Seems my old tac was off a little. I also then lowered the motor one hole and did another run.
No change exceptthe steering was over sensitive.
When I get time I will pull it out of the water and raise the motor up then give that a try.
Jkust I know what you mean and I don't want to be the fastest boat on the lake, I just wanted to be able to throw the kids off the tube.
 

ahicks

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Now that's a worthy cause!

"I just wanted to be able to throw the kids off the tube"
 
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Aug 11, 2017
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So the saga continues. .tried out a mercury black max 3 blade 15.25 x 15 that the previous owner had at one time. New hub kit. 20 mph @ 5000 rpm.
That was with the motor all the way down. Wife said she would help me pull the motor up so we did. Told her it would take a hour or so got it done with her help in less than 30 minutes. Out for a retest. Same results. I am now at the highest the motor will go. And at the end of my rope. I'll try the four blade tomorrow but at this point I'm not expecting anything great.
 
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