Condensation in pontoons?

[Jmunk]

I picked up a 1999 Crest pontoon. Backing the trailer up a friend heard some water moving around in the pontoons. The pontoons have 4 seperate chambers with plugs at the tops. I opened/broke each plastic plug and air rushed out. I was then able to siphon a few gallons of water out of each.

Since I heard air rushing out when I opened/broke off the old plastic plugs I figured they were air and water tight which leads me to think the only way water could have gotten in was from condensation over the years. By the looks of the plugs they are original and have never been opened.

Is condensation a possibility or do I have leaks ?

 

[MH Hawker]

you have leaks, think on it a moment, the air in the tubes wont have enough moisture to amount to a thimble on the day it was sealed and if sealed thats all it will ever be, so gallons is a leak, the air venting is due size of the leak and to what ever pressure the day brought by barometric pressure, temperature and sun and so on, i would think its one or several small ones in your case, those are normally around the wields where they fit on the tubes

 

[lmuss53]

You have leaks, look to the top of the M-bracket where it meets the tube in the back 4 feet, both inside and outside, I bet you'll find cracks.

Check the plugs you broke, took out. I think you'll find they had weep holes in them that are plugged up now, I think they are meant to be vents.

I put drains in the back of mine to allow for draining and water out. Once they were fixed I never had any more water issues. A 1/2 inch hole and a plumbers plug will work, but having some aluminum half-couplings welded in is a better way to get the drains.

 

[Jmunk]

Once any leaks are addressed will the brass plugs be an issue ? Should I try to source out plugs that vent.

 

[lmuss53]

I think the pontoons need to be vented.

 

[Illinoid]

IMHO no need for vent in pontoons, it will allow condensation and will allow the toons to flood faster in case you get a hole in the bottom. Mine are sealed with aluminum caps, NPT.

 

[ahicks]

Thinking I'm going to have to agree, no venting. If they were allowed to vent, any air that's allowed to enter is likely going to contain moisture, and if (when) that air cools after entering the vent, that moisture is going to settle out leaving said moisture in the bottom of the pontoon. To get rid of that moisture, you're going to need some dry air, lots of it, which that vent cap isn't likely going to see any time soon.

 

[lmuss53]

I've owned three pontoons a 90'ish Manitou, 99 Tracker and the 06 Forester I have now. I have been all over all three of them and literally dozens of other pontoons. I have a small shop at my home doing service and repairs on outboards and boats of all types. I have had pontoons repaired and shortened. I have added center logs to boats, and had transoms added to logs to install on pontoons. I don't weld aluminum but I saw all of these tubes in the various stages of the fab process. Every pontoon I have seen has had a vent of some sort to equalize pressure. All of them were also built with chambers to keep them from flooding completely in a breach situation like Illinoid described.

I'm not saying your's does, but if it does or did you should put it back that way, it is vented for a reason.

 

[GA_Boater]

Thinking I'm going to have to agree, no venting. If they were allowed to vent, any air that's allowed to enter is likely going to contain moisture, and if (when) that air cools after entering the vent, that moisture is going to settle out leaving said moisture in the bottom of the pontoon. To get rid of that moisture, you're going to need some dry air, lots of it, which that vent cap isn't likely going to see any time soon.

If that's the case, wear SCUBA gear because there is too much water in the air to support life. Only a few cubic inches of air is displaced during venting.

 

[ahicks]

And if that few cubic inches of air is replaced twice a day for 20 years or so? Do you have an air compressor that's used only on occasion? I do, and for that reason it's not drained often, but when I do, it's pretty easy to believe I'm getting a gallon from it....

 

[GA_Boater]

This does not relate. How many hundreds of cubic feet of air per minute are compressed under pressure to squeeze the moisture out of it at 50-120 PSI inside a pontoon?

1 cubic foot of air at 70 degrees and 100% humidity contains 0.00001826171 ounces of water or 0.00000304361 teaspoons. That's means it takes hundreds of cubic feet of air to even see a drop of water. In a compressor tank yes. In a pontoon, no because the air volume and pressure is not there.

Forget math - A practical test is to put a balloon over the pontoon vent in the coolness of morning and see what happens in the heat of the day.

 

[bigdee]

I have a 27 year old sweetwater that stays in water all summer long. From the time I bought it 17 years ago it had water sloshing in both logs. I have never addressed it and it does not seem to have gotten worse so I do not know the cause. I notice in rough water,water does get splashed on top of the vented plugs. So my theory is if the 'toon had been sitting out of the water in the hot sun by previous owner ( who always trailered it) and built up pressure faster than the small vents could relieve the pressure. After launching boat into the cold water a negative pressure could build up in logs and suck water through vent plugs.

 

[Jmunk]

Siphoned all the water out from the section with water, it was one middle section and each rear section. The logs have a total of 4 sections per log.

I put a low pressure guage on with a schrader valve. I put all the plugs in and put 3 psi to rear chamber. Pressure bled off slow over 15min to 0. Couldn't find a hole with soapy water. Went to next chamber on that side, opened the fitting and air rushed out. Opened up all the other fittings on that side and all were pressurized. The plugs were only in for 30min, there obviously is a hole or passage on the interior that runs inbetween each section front to back. I haven't messed with the other side yet.

I'm not sure the chambers should be bleeding off pressure to the other chambers.

 

[jsholt]

I had the same problem with my 1999 Crest pontoon boat. Every time I tried to remove the plastic plugs on top of the pontoons, the plugs just practically disintegrated. After draining the back section of my pontoon, I used a small livewell plug I bought from Walmart to replace the plastic plugs, and it worked perfectly.