I did it because I was going insane from the constant chiming noise
something inside the mast was making snip styrofoam peanuts.
Bob Swarts


That makes sense ... and I suppose foam would have solved that particular
noise problem. A very long application tube would be required initially I
would think, to be withdrawn as the mast was filled, to ensure complete
filling.

But "Rob or Karen" did then say just to plug the mast. Home Depot here sells
what's called Hotstuff (I think) foam in aerosol cans for home insulating
.... but I don't know that it would provide the desired waterproof/airproof
seal. Easy enough to find out though I guess ... plug the mast, head out to
deep water and chuck the mast overboard ... "Rob or Karen" ... let us know
how that works out :-)