How to fix leaking steel pontoons

[jeresmith72]

I recently purchased a 41' pontoon style house boat from a older man that said it was starting to list and he was unable to do stuff needed to keep it up. The house portion is still very nice yet he said when he took it out of water it looked like sprinklers coming out of the pontoons. The pontoons are steel and I checked with a magnet. Anyways I gave 3000 for boat and I work offshore as a commercial diver and sometimes stay gone for months. Im scared to put it in water and come home and find it on bottom. I know you can fill the pontoons with expanding foam but amount need to fill these big pontoons will cost me more than the boat did. Anyone know where to get the pourable foam at bulk cost or have any other ideas about fixing them. It is out of water and on trailer. It has an anode hanging off of chain under boat to prevent corrosion so not sure why pontoons rusted in first place.

 

[Dunaruna]

Re: How to fix leaking steel pontoons

It rusted because it is mild steel. An anode will provide very little protection.

The best protection is to correctly apply a marine grade, top of the range, 2 part paint. You may also need anti-foul, depending on the water.

Your toons are probably junk, the good news is that new steel toons are very cheap (in comparison to SS, alloy or glass).

 

[5150abf]

Re: How to fix leaking steel pontoons

If it is corroded enough to leak there probably isn't enough left to patch, you may get by fo awhile with aGluvit type sealer but even that will go from the inside out sooner than later.

Don't know if I would be comfortable leaving it for weeks on end.

Start pricing new toons.

 

[jeresmith72]

Re: How to fix leaking steel pontoons

First thanks for all the advice. I pressurized pontoons and there are about 4 small leaks on just one of the toons. They do have a black very hard paint that looks like epoxy on them already and on the bottom of them from around 3 oclock to 9 oclock they have a thicker coating of some kind of paint that I can tell was brushed on. I have looked thoroughly and can see no visable signs of rust anywhere on toons and they sound very solid when I hit them a a hammer. I even removed paint in a couple spots to see if I could see signs of pitting but didnt. The houseboat was used on a lake in louisana and had a bunch of small to medium dents from hitting stumps and logs, and I think that these might have caused leaks or definately didnt help. Should I strip off or sand blast off old coating and redoo with stuff you mentioned or possibly get some flat steel plate thats similar contour of toons and weld it like double hull. I am an underwater welder and could possibly do it myself.(I think!) And if they were filled with a good closed cell foam wouldnt they stay bouyant for along time since water would have no space on inside to occupy even if they did leak. And is there something I can pour into ports on top of each chamber on pontoons to displace water or slow down or stop rusting from inside from water that already got in.

 

[Dunaruna]

Re: How to fix leaking steel pontoons

Once you have moisture inside, the rust process continues regardless of how much repair and paint you add.

If it were me, I would clean the areas around the holes back to bare metal and assess the condition of the structure. If they are punch holes (and not rust), i would repair with a 4 mm overlapping sheet, you will need a mig and some welding skill. Blowing holes in thin mild sheet is very easy. You will then need to prime and recoat the bituminous 2 part paint. Then gain access to the toon to try and dry it out.

I got fed up with the constant maintenance on my steel toons, I decided to replace them with 6 mm alloy.

 

[5150abf]

Re: How to fix leaking steel pontoons

Okay so it isn't as bad as your original post made it sound, Fix the leaks that you found but I would stay away from foam, once it gets water logged it will never dry out and that muhc spray foam may cost you as much as a new set of toons.

If you were to sand blast the tubes then you would know exactly where you are as far as corrosion and it would make it easier to find and fix leaks.

You can rent a sand blaster for very little for a weekend.

 

[jako58]

Re: How to fix leaking steel pontoons

Okay so it isn't as bad as your original post made it sound, Fix the leaks that you found but I would stay away from foam, once it gets water logged it will never dry out and that muhc spray foam may cost you as much as a new set of toons.

If you were to sand blast the tubes then you would know exactly where you are as far as corrosion and it would make it easier to find and fix leaks.

You can rent a sand blaster for very little for a weekend.

Once you've fixed the leaks you can see, the next concern is where the next leak will appear. You need to arrest the corrosion that's going on inside your pontoons. Automotive antifreeze is chock full of corrosion inhibiters to protect your engine. Buy a long life or permanent formula (as those have the highest level of corrosion inhibiters) and add some to each pontoon. The antifreeze will easily mix with any remaining water, will disperse itself with the motion of your boat, and will go very far to arrest the corrosion at it's current state.

 

[5150abf]

Re: How to fix leaking steel pontoons

Weclome to iboats jako.

Generally they frown on digging up 3 year old post, the original poster is long gone, thisnk of these older posts like library books, they are grat for information but you don't write in them.

Now you know and please keep posting just do it on current threads.