I'm kind of guessing, but I'd bet reg spar varnish. I think they both have UV inhibiters. Borrego might know. jerry ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Thursday, September 27, 2012 4:24 PM Subject: M_Boats: varnish Hate to get off the interesting thread about teeny motors, but I have another question; what resists UV best on a boat in the sun: standard spar varnish, or urethane spar varnish? Additionallly, I now have numerous coats of regular varnish in good shape, and I wonder if the urethane would go over the regular without sanding to bare wood (which I ain't doing). Thanks, Tom Jenkins -- I am using the free version of SPAMfighter. SPAMfighter has removed 7229 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len Do you have a slow PC? Try Free scan http://www.spamfighter.com/SLOW-PCfighter?cid=sigen