Help with very old Pontoon repair

[GrandaddyV]

Hey ... long story long... sorry ...

Replaced an old 55 gal drum floating dock with a pontoon frame ... 2 pontoons and just the aluminum floor frame. Folks I bought if from said it's high/dry ... doesn't leak, etc ... and it "seemed" after observing on 2 different occasions that was the case.

it's about 23-24 feet tubes... there are 4 - what i'll call air valves ? about a 3/4" pvc threaded hole with square threaded plug in each.

So after putting runners on the frame and my decking ... done partly on land and later on the water... I begin to notice the front left (starboard) pontoon dipping, lower in the water, etc. ...

Due to nature of mounting, decking, etc there is not chance of a screw puncturing either pontoon anywhere ...

Now the problem ... I don't really have an easy way to get this out of the water .. it's a 50 acre lake... don't have a typical boat ramp... 'might' be able to 4x4 it out on a trailer ???
Even then the pontoon will be on the trailer so I'd have to (i guess) jack the pontoon up while on the trailer and try and determine where water is , drain out then find the leak...

now while it is in the water ... can I remove one of those PVC fixtures on starboard side and see if any water pumps out ? ... If so I'm guessing that will at least help ID where the water is/leak is at ?

If it seems to be just in that starboard side that's holding water... what's the change of being able to seal leak with is sitting in water ? closed cell foam ?

Obviously after reading the above I'm needing any help or suggestions ...

Thanks David

 

[ahicks]

No real helpful ideas I'm afraid, but I would NOT use foam! That's just going to make a sad situation worse....

 

[Silvertip]

If the unit is IN the water, pressurize the tube (low psi) with whatever fittings you need for the bung. The any water IN the tube will be forced out through the leak via the pressure in the tube. Remember that you can rupture the tube with too much pressure. Just a few PSI is all that would be needed. You should then be able to see bubbles from the area of the leak. A sheet metal screw with a rubber washer and some sealant would seal the hole. If it doesn't work you aren't out much cash.

 

[Grub54891]

It may take awhile for the leak to show. The low air pressure will have to push the water out first.

 

[ThomW]

You can pull the plug on the top of the section you think is leaking and pump most of the water out with a hand pump and tube. Then applpy the air...that way you wont have tro wait as long for water to pump out the leak.

I know my toons have 3/8 threaded holes on top. When mine had a leak, I took a brass elbow and screwed it in, then used low PSI air from a compressor into the fitting and looked for bubbles. The pontoons should have baffles or walls between the sections to keep it from sinking if one section leaks....but they can fail. So when you are putting air in, look all the way down the toon, not just the first section. Best bet it to pressure check each section on the toon and see which hold air and which bubble.

As far as foam...I highly recommend NOT doing that. I have a pontoon I am in the process of "fixing" after the previous owner used closed cell foam in the toons to "fix" a leak. Even though it was closed cell, after there was a leak and a few years passed, it became waterlogged foam and added hundreds of pounds of weight to the rear end. Getting that foam out of a small cut hole is one of the worst things I have ever tried. Find the leak and seal it....

 

[Scott Danforth]

the vent at the top of the tank is for you to periodically pressure test the toon log chambers. 1-2 psi max.

the typical leaking point is the M-bracket at the top of the log will crack along the welds.

to properly repair the toon logs, you should be on the hard.