Pontoon diameter for a houseboat

[boatbuildertom]

I am working on plans and ideas for an 8.5 ft. x 28 ft. houseboat, powered by a 90 hp. outboard, that is trailerable. I want the pontoons to sit a little higher than most pontoons you see in the water. The pontoons are not quite big enough, because the weight of the motor makes it sit low in the water.
My total weight excluding the toons would be about 3700 lbs.
I was thinking about using 36 in. diameter tubes, so there will only be 2.5 ft between pontoons for the transom. Is that enough room?
What do you experts think?
Will it sit to high in the water and be unstable?
Should I go to a smaller size toon, such as a 30 in. diameter?
Any other ideas or suggestions that might help me decide on the size toon to use?
Has anyone had experience with the plastic pontoons that are now available?
Thanks Tom

[RonKMiller]

I'm no expurt, but thought this may help.

I'm currently working on a 28 foot tritoon that I've turned into a flatbed (actually it's a 2 and 1/2 toon) that will have a 2000 lb. travel trailer on top... It's got a 90 horse Yamaha. My logs are 21" diameter. It's a 1987 boat...

With all my gear, fuel, engine, trailer, furniture, yadda yadda and 2 passengers I should have about 1,000 lbs. to go to my max allowable loading.

[badmoonrising]

My Party Cruiser (32 ft and 5500 lbs) has 28 inch logs and sits pretty high out of the water. There was a guy at the other pontoon site that used composite logs and hated them...last I heard he planned to remove them and go to aluminum. He had an older Party Cruiser and added 2 composite logs on the inside. Didn't look that great either.

[BassFrequency]

My Party Cruiser (32 ft and 5500 lbs) has 28 inch logs and sits pretty high out of the water. There was a guy at the other pontoon site that used composite logs and hated them...last I heard he planned to remove them and go to aluminum. He had an older Party Cruiser and added 2 composite logs on the inside. Didn't look that great either.

are u talking about that big assed 42' pontoon from wisconsin? what ever happened to that guy?

[dockholiday]

Have you given any thought of making a tripple aka tritoon, using smaller dia logs ? Normally the center toon is 4 to 5 feet shorter, so that might solve the transom issue. The tritoons usually sit a little higher than comparable 2 logs.
doc

[Bamby]

Have you given any thought of making a tripple aka tritoon, using smaller dia logs ? Normally the center toon is 4 to 5 feet shorter, so that might solve the transom issue. The tritoons usually sit a little higher than comparable 2 logs.
doc

I think Doc has made a good suggestion for your application. A Tri-toon configuration would provide the additional flotation your desiring, plus some additional benefits. First and foremost it could or would allow you to use more readily available pontoons that may be available on the market. And secondly and also important especially in a "houseboat" is that tri-toons are somewhat more stable in rough water. I've observed that two loggers vs. tri-toons that two loggers just seem to rock both more and more violently when passed by a cabin cruiser for instance. Not saying a tri-toon which our is doesn't rock "it does" but it's much more like a roll that seems to even stabilizes out much faster than a two-tooner after experiencing a wake event. And stability is an important factor especially in "houseboats" where we tend to have a lot more baggage to be potentially displaced out of the cabinets and onto the deck or floor.

[badmoonrising]

My Party Cruiser (32 ft and 5500 lbs) has 28 inch logs and sits pretty high out of the water. There was a guy at the other pontoon site that used composite logs and hated them...last I heard he planned to remove them and go to aluminum. He had an older Party Cruiser and added 2 composite logs on the inside. Didn't look that great either.

are u talking about that big assed 42' pontoon from wisconsin? what ever happened to that guy?

Yeah it was a 32 footer factory and he rigged swim platforms on the bow and stern to make it a 42 footer. He left PDB because he always got into arguments with the regulars and then complained to Brady when he lost debates (a liberal, need I say more ). He was at pontoon stuff for awhile. I'm banned there too (although all I did was sign up and they locked my account ) so I don't know if he still is.

I had to ban him from my site for creating multiple log ins and causing other problems there too.