Thanks all.

Alex, excellent thanks..
I'm assuming tape inside and out?
and what did you seal the wood beyond the tape lines with (i'm considering a two part floor varnish as it's free then an opaque colour)

: Just tape the seams, inside and out.
: 3 mm.
: My oldest kayak was built in the mid 1980s, still use it at times,
: 4 mm?, only glass on the seams. Second kayak, 1990(?), a hard 10
: years of use, still used, 4 mm, no glass over, only glass on the
: seams. Third single is 10 years old with 3 mm ply. The kayak I'm
: usually paddling now is 2 years old, 3 mm ply, glass on seams.
: My partner's kayak, she built it over 10 years old, 4 mm ply, no
: glass except the seams. We paddle around rocky shores and the
: kayaks get hammered at times and survive very well. Day trips
: and multiday trips.

: Alex