Marine: Boating, Sailing, PWC, GPS and Navigation - Do all pontoons leak?

It seems our pontoon logs ALWAYS have water in them. We have siliconed and siliconed the plugs. Could it be taking on somewhere else? Is this supposed to be common knowledge? I feel not so smart! ~~ Thanks!

How much water are you getting out of your Pontoons? A little is natural just from condensation, maybe a few cups at the end of the season. If you are concerned that it could be something more than condensation you can pressure test them. You'll have to find/make an adapter to go from your drain plug threaded fitting to a schrader valve so that you can fill the pontoons with compressed air. You can then use soapy water to check for leaks, as you would with a leaking tire.

Hope this helps.

Yes, it might be possible to test pontoons with compressed air but to do so carelessly could kill or maim you or anyone nearby.

This is a specialized test and should not be done by a novice.
You need a two stage regulator and a low pressure relief valve that folks just won't have.

Describe in deatil how the pontoons are constructed as far as seams go and how the pieces are put together.

A lot of them here do have a schrader valve in them on the top some place . With a drain plug on the top, near the back . This has a pipe in it that goes down to the bottom of the log. So any water in the log blows out when you put air in it.
Im with GregH here for sure . Had a friend put a air compressor on his to check it out. Poped open a seam at the bow with about just 5 lb psi. If you go that way try a air hand pump.
Dont forget there always is good old 3M 5200

has to be gallons - several times the last summer. More than a few cups. I couldn't describe the pontoons right now - it's dark here - but I will look for that other valve - and will sure take the hand pump suggestion to heart! thanks!