Water In Pontoons As Ballast?

I spent this past weekend helping a buddy restore a pontoon boat that he recently purchased. It's 20' long with a 70 hp Johnson and was built around '87 or '88. Each of the two pontoons is divided into a forward chamber and a separate aft chamber - for a total of four chambers.

The boat was on the trailer when we moved it and heard water sloshing around. Since there was definitely water in the pontoons we thought that we might have a cracked weld. When we removed the plug from the top of each of the four chambers, however, we heard air escaping. (It was a warm day so a slight amount of air pressure had built up.) The point is, each chamber had watertight integrity but contained a significant amount of water. When we launched the craft we noticed that it set perfectly level - no list or trim. Water level outside the pontoons was about half way up the outside.

The craft has apparently been used to fish bays and canals around the Gulf Coast. Of course the coast can get fairly choppy at times. I've also heard that while pontoon boats are very stable they can also get tossed around a little bit. It therefore appears that the water was deliberately added as ballast. We took it for a ride on the bay and it seemed to ride just fine. As you would expect, however, gas mileage was not so great since we were carrying around a lot of extra weight.

So, is water routinely added to the pontoons on these boats or is this just bad medicine used to trim the boat out or ballast it down and make it ride a little better? Regards - Woodnaut

Re: Water In Pontoons As Ballast?

Never heard of that, but it sorta makes sense. I'd try removing all the water and doing another test. I'm betting it'll still ride level and you'll get better fuel economy and speed.

Re: Water In Pontoons As Ballast?

could be years of condensation, they are suppose to be dry.

Re: Water In Pontoons As Ballast?

I would think enough water to make a difference as ballast would cause handling issues as it sloshed around when slowing, accelerating or turning.

Re: Water In Pontoons As Ballast?

Drain them and don't look back.

Re: Water In Pontoons As Ballast?

I just bought a 20' pontoon boat also and it had fills and drains on it. The guy told me that it also was used for water ballast which I had not heard of before. As the tubes are one long tube I'd be very concerned that the water would shift around without baffles in there thus I would not do it. Although it's be a good way to see if the pontoons leaked by filling em up a little and seeing if they leaked while on the trailer.

I plan to hook up my compressor and pressurize them up to 10psi or so and see how long they hold the pressure to see if they're good tubes or not.

Re: Water In Pontoons As Ballast?

samo_ott said:

I plan to hook up my compressor and pressurize them up to 10psi or so and see how long they hold the pressure to see if they're good tubes or not.

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That sounds like a better plan than filling them with water. They would get VERY heavy!!

Re: Water In Pontoons As Ballast?

I've never heard of such a thing as using water as a ballast in a pontoon. That simply does not make sense to me. Don't get me wrong, I understand what a ballast would do, but not in this application. I would drain them and keep an eye on them. Maybe some was leftover from a previous leak that was repaired, or, as TD said, condensation? Are there any signs of repairs (out of place welds)?

Re: Water In Pontoons As Ballast?

All submarines use water for ballast. Fill the pontoons of a pontoon boat, and you will have a submarine.
Ballasted down, means only partially sumerged.

Re: Water In Pontoons As Ballast?

NOOOO, pontoons don't use water as a ballast. period.....The drain holes are there for letting water out in case or cracked pontoons or such.
I actually think you're not supposed to put more than 5 lbs of air in a tube..Even then I don't think you are supposed to do it.. yes on a hot day they will expand and all.
There are Forums just like this one for pontoons. Before you go doing anything to the pontoons... find the Forums and ask....
If you have water in the toons.. you've got a problem somewhere.
Subs and a brand of sailboat, which I believe is called MacGregor uses water ballast. I'm sure there is more, but not a Toon....

Re: Water In Pontoons As Ballast?

fishntoss said:

NOOOO, pontoons don't use water as a ballast. period.....The drain holes are there for letting water out in case or cracked pontoons or such.
I actually think you're not supposed to put more than 5 lbs of air in a tube..Even then I don't think you are supposed to do it.. yes on a hot day they will expand and all.
There are Forums just like this one for pontoons. Before you go doing anything to the pontoons... find the Forums and ask....
If you have water in the toons.. you've got a problem somewhere.
Subs and a brand of sailboat, which I believe is called MacGregor uses water ballast. I'm sure there is more, but not a Toon....

Click to expand...

You might not have any problems with the toons at all. The previous owner may have added water for stability and did not care about speed and performance when putt-putt tooning at 3 knots.

But if your gonna trailer it, you don't want any water in the toons as they are not designed to carry water when out of the water. They could buckle if not properly supported when out of the water. Plus your trailer could be grossly overloaded.