Dear Vega Sailor,
I had the same trouble with mast leaks during many years.
Firstly, I connected a toilet socket on the mast foot and had the wiring
throu this narrow opening. I helped, but the rubber toilet socket started
to corrode.
Then I did what most Vega Sailor do in The Netherlands, I made holes in the
side of the mast and
the electric wiring now come out of the mast into fitting outside the mast.
Its not so pretty , but very effective.
Of course I closed the mast opening totally, so that no more water come
trough any more.
I hope my english is clear enough. Good luck!
Regards,
Henk Jansen
Le Cygne V 1782