I had an issue with the portlights leaking also. I talked with Lewmar,
who provided a fix. Mine are the "old standard" used on boats from 1980 to
1998. They are about 7-1/2" by about 14-1/2" , with the rotating locking
dogs on the interior. There are two horizontal joints on the exterior of
the frame, one on each side. I had talked with Catalina Direct, who first
suggested o-ring replacement, which I did, and then tried the silicone
grease to soften the gaskets, both with no resolution. Lewmar provided a
fix for frame leaks, which I have attached. It is simple - "To fix the
leak, do not remove the portlight from the boat. With the portlight in
place remove as much of the gasket material from [the horizontal joints on]
the outside frame as possible and replace with silicone sealant." I taped
each side and applied as much silicon sealant as I could force into the
joint. The leaks are gone! Good luck.
John Stetson
Morning Star...Again
Hull #578
Shelburne, VT