Thanks, Jim. I think I am sold on varnish over Cetol, but
when/why
should you use polyurethane varnish instead of the "regular"
stuff?
The local boat store sells both varieties under the Goldspar
label.

You'll find as many opinions about polyurethane varnish vs
"regular" varnish as fish in the sea. I'm personally a "regular"
guy (no cracks).

My experiences with two part poly were not very satisfactory. It
was more critical to apply, and when it aged, it came off in
sheets. Now this may have been bad application in my part . . .
but there is a general consensus that 2 part poly is not very good
with UV.

One part polyurethane I haven't used. Again, I understand it is
not so resistant to UV, though you will find it sold in "exterior"
grades.

"Regular" exterior grades I've used on everything on the boat
(except the bathing ladder steps and the deck - both teak -
unprotected). OK, you need lots of coats (6) first time round, but
it's easy to touch up, and adding an extra coat or two after a
light rub down for the next season is a doddle.
--
JimB
http://www.jimbaerselman.f2s.com/
Describing some Greek and Spanish cruising areas