A local cabinetmaker uses many coats of spar varnish (just a varnish designed to
stay flexible so it moves with the wood in an outdoor location - I can tell you
a good story) and polished it through the grits and with power polishers so it
is gorgeous:

http://www.viccovonvoss.com

Having done my share of spar-varnishing, I would not have thought you could
polish it so succesfully.

Ed Minch