I just refinished my cockpit table and the companion way boards.
I did it the old school method, seven coats of epiphanes spar varnish, sanding between each coat and thinning the first 3 with mineral spirits.
Take the old finish off using a heat gun and scraper, sand it using 100 grit and then de grease using acetone. You can use an orbital for this sanding process only, not for the in between coats mentioned next.
Bring the project indoors, temperatures no lower than 65F and humidity no greater than 50%.
Apply the first cost thinned 1:1 with mineral spirits. Wait 24 hours between each coat (2 sides means 48 hours before each new side).
Thin the second coat by about half, thin the third coat by about 25%.
Hand sand the thinned coats using 320 grit, then the full coats using 220 grit.
You will need to put a maintenance coat on every six months to a year, for the exterior finishes. Its relatively easy to do, if you keep up with it. Just light sanding or even a 3m pad to scuff the surface, then apply a single coat.
There is really nothing like it!
Eric
Moon Taxi, H44, #22
Fernandina Beach, Fl