pontoon to tritoon conversion

[Chas4273]

If you could get the prop make/model/size/pitch sometime I'd appreciate it. You're getting 10+ MPH more than mine, with the same motor. Think our boat weights are comparable, although mine has 25" logs.

[Mikearmentano]

Might be the smaller pontoons. I took a 25' Bennington for a test ride with their oversized elliptical pontoons. The boat did 35 mph (GPS). It wasn't as fast but it carved through the water much better than my aqua patio. Do u have lifting strakes? I'll post prop make/model/size/pitch soon. I should also say, at times, with 5 people on board, my top end was only 33 mph. That was with the original prop. With the new ss prop, I should consistently get 35 mph with the same load. With the current setup of only 2 pontoons, performance declines if 3 or more people are sitting in the bow. The 3rd pontoon should make a big difference.

[pond tuuunes]

On my tri tune, as soon as 2 people sit in front of the helm, im down 8 mph, but after that i can fill the boat up with people, and it stays the same. JT

[Mikearmentano]

JT, do u have lifting strakes on all your pontoons?

[pond tuuunes]

Both sides of the center, and only on the insides of the outer toons. JT

[Mikearmentano]

Chas4273 I talked to my boat dealer and explained your situation. Listed below are my specs on my propeller but he didn't think that was the problem. Here is a copy of the email he sent me:

Hi Mike

It has more to do with Bennington nose cone profile. Bennington as a whole just don’t “plane” well at all, no kidding around. They are slow as mud. I have customer up in Sherman with a Bennington 25’ RL 150 Hp, strakes.. had a bad relationship with his dealer brought it to us, they had is set up all wrong, motor to deep, wrong prop etc, we sorted it out, but still after tuning it in correctly the max we could get it to run was 33 mph on GPS w/ Clean tubes. I drove a Bennington 25 with that ellipitical tube in the center, and a Yamaha 250 Hp SHO motor. 36 mph was all it would go. It was set up wrong from the dealer which didn’t help, but a F 250 SHO will push a dock at 36 mph.

Your boat has a Yamaha 15 pitch factory polished Stainless. I would be relatively sure that a Bennington w/ a 150 Hp will not be able to spin that pitch prop. He will have to go to a 13 pitch. (The boat has too much drag with the nose cone/ motor pan design they have) to get the engine into the proper operating RPM range. 5200 +

Marc - Echo

If he wants to be kind of fast, he owns the wrong brand pontoon boat: Faster boats: Premier, Manitou, Playcraft Medium Boats: Godfrey , Harris, Berkshire Stuff Slow Boats: Bennington, Crest, Tracker


I hope this helps.

[Chas4273]

Thanks for posting that letter! Top speed isn't a huge deal to me, but I would like to get the most out of my boat as possible. So far the fastest GPS speed I've had was 29.6mph with about 650 pounds of people on board. That was with the stock Yamaha 15m aluminum prop spinning around 5500RPM (can't remember for sure). Now have an Enertia 15x15 and lost too many RPMs. Will have to go to the prop shop and see what I can swap out for--sounding like I need to drop down even further than I thought.

[blackghost16]

I just got done building a DIY tritoon kit, I bought a spare pontoon, and built my transom INTO the back of 1 of the toons, then i mounted the entire works under my boat utilizing the existing bolt holes for the transom, and then drilled out the remaining holes for the new toon in front, it all lines up in the front, i had to install a "bay engineering" 5" extension kit to drop the prop below the toon. HOWEVER when i get it on the water i thought that i would have more buoyancy (which i do) but i did not realize that i would not have near the amount of "LIFT" on the front of my boat as i had before installation. I understand that my little 50HP merc is not a power house but i didn't realize how flat my boat would ride even at WOT. my concern is that as i load up with people and gear i will not gain ANYTHING in regards to buoyancy because i wont be able to get on plane. did anyone else have this issue? Im scared to load it up if it is going to just take on water.... thoughts?


I guess i should explain a little bit better, before i mounted my center toon, my motor would lift (essentially wheelie) the front of my boat when i hit WOT. HOWEVER when i came off plane it would essentially nose dive when i had a heavy load. Now it seems that i do not get the wheelie effect, but instead it barely gets on plane. any advice would be awesome its a 2004 20' misty harbor with a 2003 50HP auto feed 2 cycle mercury outboard.

Sitting in water with a heavy load is great, i can easily handle more weight as my center toon adds so much more buoyance, and it turns like a school but now... but again my concern is that i will be loaded with family/gear and bury my front end again, even though I have the added buoyancy.

[Motor7]

I'm no expert, but you need a bigger engine.....go with a 90hp minimium.

[Rick McC.]

I don’t think that 50 HP is enough power to provide much “trim” capabilities, much less plane, a tri-toon.

[steve1313]

Ummm.. This is an 8 year old thread and the OP hasn't been around since then LOL

[Motor7]

Ummm.. This is an 8 year old thread and the OP hasn't been around since then LOL

We were responding to blackghost....

[Rick McC.]

Ummm.. This is an 8 year old thread and the OP hasn't been around since then LOL

We were responding to blackghost....

Yep.