pmemsmer,
It sounds like there just wasn't enough sealant.
I replaced all of the
hatches and ports on my Cal 34 about four years ago. The
hatches were a standard size and fit the existing openings, I only had to drill new screw holes -- but I had to enlarge the cutouts in the cabin sides to accommodate the new
Lewmar portlights. As long as the products themselves don't leak, then I would suggest going overboard with the 4100 or something similar. Just goop it on, let it squish out the sides and clean up the excess with a rag and acetone. No leaks since.
S.