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Adding boyancy to a toon?
Posted: Tue Nov 04, 2014 6:53 am
by wijames
I just purchased a 20' sylvan tritoon. It's a 2000 model so obviously the third toon was added later. I noticed when it was delivered that it rides very low in the water in the back, even with only one person and no gear on it. It does have a large, heavy Honda 90 four stroke on it. is there any way to add boyancy to the back of a toon?

Re: Adding buoyancy to a toon?
Posted: Tue Nov 04, 2014 7:15 am
by teecro
Several curious questions come to mind here. Your right it does seem to be sitting rather low in the stern. So first off I wonder if the added toon is too short and positioned too far forward? An overly buoyant bow could be forcing the stern deeper. Is there perhaps water trapped in the rear of the toons? How does it perform while underway and up to speed where does the motor cavatation plate run; at or near the surface?
Re: Adding buoyancy to a toon?
Posted: Wed Nov 05, 2014 6:26 am
by wijames
teecro wrote:Several curious questions come to mind here. Your right it does seem to be sitting rather low in the stern. So first off I wonder if the added toon is too short and positioned too far forward? An overly buoyant bow could be forcing the stern deeper. Is there perhaps water trapped in the rear of the toons? How does it perform while underway and up to speed where does the motor cavatation plate run; at or near the surface?
All good points and I'll get answers to most of them this weekend. I do know that the third toon only goes about 3/4 of the way to the back of the boat to where the engine gunnel starts. That has also been changed to a newer all aluminum transom model. And in the picture I realized that the boat was in reverse which would have brought the back down a little. I've never pulled the plugs on a pontoon to check for water. Are there any special precautions I need to know when I do that? I did notice that my boat has plastic plugs at the bottom of the toons.
Re: Adding boyancy to a toon?
Posted: Wed Nov 05, 2014 6:51 am
by curtiscapk
pull those plugs and measure how much water comes out. I bet you'd be surprised.... Mine doesn't have plugs and I can hear the water inside. I am going to put some plugs in in the spring.
Re: Adding buoyancy to a toon?
Posted: Wed Nov 05, 2014 8:24 am
by teecro
wijames wrote:teecro wrote:... Are there any special precautions I need to know when I do that? I did notice that my boat has plastic plugs at the bottom of the toons.
Plastic is good in that it does not corrode and get stuck like any other metal would in alum. Just try to not let the wrench strip the soft plastic, and don't over tighten them when replacing. It can help the draining if needed if you also remove an upper plug too.
Re: Adding buoyancy to a toon?
Posted: Wed Nov 05, 2014 11:00 am
by wijames
teecro wrote:wijames wrote:teecro wrote:... Are there any special precautions I need to know when I do that? I did notice that my boat has plastic plugs at the bottom of the toons.
Plastic is good in that it does not corrode and get stuck like any other metal would in alum. Just try to not let the wrench strip the soft plastic, and don't over tighten them when replacing. It can help the draining if needed if you also remove an upper plug too.
Thanks for the info. I haven't seen any upper plugs but it makes sense that they would have them. I'll give it a better look.
Re: Adding buoyancy to a toon?
Posted: Mon Nov 10, 2014 10:55 am
by wijames
Well I pulled the plugs this weekend while the front was about a foot and a half above the back and not a drop of water came out. Left to for about 10 minutes and nothing. I get get a whoosh of air when I pulled the plugs though. I love the plastic plugs, just changed the o rings on them and back in they went.
Re: Adding boyancy to a toon?
Posted: Mon Nov 10, 2014 2:11 pm
by yellowk9
I think you just have the smaller diameter toons like me. Having the third toon only towards the front adds buoyancy there and may tilt the back down a little. My 20' Sweetwater has two 23" toons with a 90 hp Suzuki and sits pretty low like your boat.