An alternative, if you don’t mind a more “traditional” look, is oiling
exterior teak. That has been my choice on this boat and my last one.
Every 6 months I scrub the teak with a 3M-type scrub pad, using a
diluted mix of detergent and some bleach. Rinse well, let dry, and rub
in a couple of coats of store-bought or homemade teak oil. Looks like a
million bucks for a week or so, then turns grey – as teak was meant to
do on a boat. This twice-a-year, half-day job keeps the wood healthy
forever and avoids years of sanding it down. When I was ready to sell my
last boat after 6 years of non-stop cruising, I put on a few coats of
varnish for the glitter effect. The teak looked factory new!

The other alternative is paint, but it’s best to first varnish the teak
and then paint over that so the paint doesn’t get into the wood grain.
That way it can be stripped off in the future if you or a new owner want
the natural teak again.

Tor