Help with Pontoon haul design.

[turbom700]

Long story short I built a I/O pontoon a few yrs back(viewtopic.php?f=16&t=21589) thought I would be happy with a 140hp and 27mph, but like anything I cant leave well enought alone and have been aquiring parts to back it better.

I should have "enough" horsepower now. Just got the LS1 off the dyno and made a little over 400hp and picked up a bravo drive to handle the HP.

Now onto center toon design. Looking for something that will plane better, after looking at all the other manufactures I came up with this.


I'm wondering if I should change the back "current" portion to have a flat bottom or leave it and it might act like a step, like the preformance v-hulls have. Thoughts?


This is what the current boat has, the issue I have is the back of the boat planes quicker then the fron thus driving the front of the boat down.

[BoatCop]

I don't think there are any marine engineers on this forum that would be able to answer your question. And even if there were, more information would be needed to assist you.

Going from a 140 HP 4/6 cyl to a 400 HP V8 inboard would take a lot more than just adding a motor pod. An engine that size/weight/power output would require a complete engineering work up, with center of gravity, displacement, weight, weight distribution, etc. all coming into play.

With just throwing a 400 HP V8 w/ Bravo One outdrive on it, may I suggest a re-commissioning name of "Deathtrap I".

[turbom700]

Haha lets be honest the amount of engineering that goes into pontoon hauls these days isnt much at all. Looking at other manufactures of pontoon you can clearly tell this and I'm a ME by trade I do this stuff for a living. Not the marine side but the ORV side.

I dont care if there is a 140hp or 400hp the boat will handle and plane better with a single toon then a split toon for a center toon.

Infact the difference in weight between an alum LS1 v8 and bravo and a 4cyl 140hp isnt more then 200 pounds.

You might be right about No marine engineer on here but there are some smart people that might have words of wisdom. Other than calling it a "deathtrap"

"Fear is the thief of Dreams"

edit:
Lots of engineer went into this, looks complete different then the same haul they put a 350ho in.

[Cowracer]

*hull


Tim

[JBO]

*hull


Tim

Agreed. I think the hull design needs looked over.

I doubt you'll find any mechanical engineers on here wanting to give professional advise on that type of conversion. If you're a ME yourself, I'd say you're probably the smartest guy in the room.

[OldePharte]

Got any test tank setups where you could do a scale model test on the various designs like they do for aircraft?

[rancherlee]

Looks very similar to the Premier PTX center hull. The PTX was originally used as their I/O hull without strakes on the outer tubes and a few years later became the "PTX performance hull" for outboard engines and strakes were added at the same time to insides of the outer tubes. I just about bought an older Premier I/0 with a bad engine to convert to an outboard performance toon. Flat is the best planning surface but it needs a lot of support. The flat bottoms on my pontoons are concaved now after years of use as mine was never designed to be a "planning" pontoon and built out of thinner ~ .070 and supported only every 4' by a bulkhead. The PTX uses .125 with support ribs closely space just like any other aluminum v hull boat

[turbom700]

Looks very similar to the Premier PTX center hull. The PTX was originally used as their I/O hull without strakes on the outer tubes and a few years later became the "PTX performance hull" for outboard engines and strakes were added at the same time to insides of the outer tubes. I just about bought an older Premier I/0 with a bad engine to convert to an outboard performance toon. Flat is the best planning surface but it needs a lot of support. The flat bottoms on my pontoons are concaved now after years of use as mine was never designed to be a "planning" pontoon and built out of thinner ~ .070 and supported only every 4' by a bulkhead. The PTX uses .125 with support ribs closely space just like any other aluminum v hull boat

Thats the type of information I was looking for, Thanks

This will be made out of .125 5052 bent out of one peice, should be plenty strong.

Will also have ribs that tie into the main cross beam stucture ever 2ft.

I have rode in many of the performance pontoons and it seem the PTX has the best ride and quickest onto plane times, that why I "copied" there design some what. They only run about 6" pad put its lower to the bottom of the toons, thus there motors sit lower. I'm trying to get away from this.

[ToonGuy]

I think as long as your transitions are smooth and minimal you'll be fine.

I'm going to go out on a limb here and say there's not as much to these performance toons as some think. Yes, manufactures have done research, but remember there's a difference between research and "sales hype". It doesn't take too much for a DIY guy to copy a few features and get great performance. That's not to say it will absolutely optimal right out of the gate, but most DIY guys aren't looking to break any records either.

My first ground up build geared towards performance went an even 40MPH with an old 1984 Johnson V4 140HP. It wasn't a perfect boat, but it did more than I had hoped for. You're already on the right track by improving to a "full" center tube. Keep playing around with ideas and I'm sure you will come to the one you like the best, and I bet you'll be pleased.

And don't forget lots of pics