The top of my mast is not sealed on a Mystere cat, so you're right the problem is that extra 30-50lbs of water in the end of the mast is causing major problems.I have what appears to be a bouy type from a boat customized at the top, holding it's own and not leaking. so i think with a little more experience, that means more time in the drink, i may get a handle. Our lake is 5x7 miles and typically someone is out to help, but i don't wan't to rely on them.
You can see this, attached picture!
thanks Paul