Re: Sealant for drain plugs??
These plugs are on top of the tubes or below the water line?
An easy way to check for water, if you have a trailer, is to just get the boat moving and stop suddenly then just listen for water sloshing around, may have to put your ear against the tube obviously requires 2 people.
I have never understood why anyone would put plugs on the bottom of the tubes, its like they know the tubes are going to leak so they may as well make it easy to get all the water out.
The plugs actually have nothing to do with water removal, they are to vent the tube so it can be welded, can't weld a closed cylinder cause it blows out, and to put air in the tube to check for leaks, unless they are on the bottom.
Another thing people don't realize is a hole in the top of tube is actually worse than a hole in the bottom, you could, in theory, drill a 2'' hole in the bottom of the tube and if there are no other holes very little water will come in, put a glass into water upside down, same pricipal.
To answer your question some teflon tape should work nicely.