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I have been told that a clear finish is better than paint for the bottom of a racing boat. I assume that is because finishes like epoxy or varnish sand out better than traditional paints (epoxy-based paint would be an exception, presumably). In the end, finish your boat as you see fit.
I finished the bottom of my Pro Vee with one coat of epoxy resin, followed by four coats of spar varnish. BUT this lead to a problem discovered a few months later.
Spar varnish is not meant to be used below the waterline. That is, it is not supposed to be continuously wet. This should not be a problem for a racing boat, which spends most of its life on a trailer and only brief periods on the water. However, the pad of my Pro Vee rests on a single, wide bunk down the middle of my trailer. The carpet on this central bunk is constantly wet or, at best, dries very slowly. After about three months of living on this trailer, the varnish on the pad was peeling away in the worst areas and rough everywhere else. I sanded the pad back down to wood and refinished (the pad only) with four coats of epoxy. The remainder of the bottom is still varnish over a coat of epoxy and is doing just fine.
If you choose to finish your bottom with epoxy only, three or four coats will probably be needed. Apply it with a roller, then tip it off with a foam brush. A small amount of silica thickener might be a good idea to help avoid any sagging.
You could also finish with varnish only, skipping the initial coat of epoxy. Four or five coats would be recommended with light sanding between coats (or whatever the manufacturer calls for).
Sand your finish glassy smooth, paying particular attention to the pad and the aft-most four or five feet generally. Areas forward are only in the water at slow speed, but some parts will be wet when turning; don't entirely neglect them.
I chose to seal the wood in my cockpit with epoxy, a single coat, lightly sanded afterward just to knock down any roughness. I paid particular attention to areas where water would pool -- mostly the keel and bottom plywood aft of bulkhead four.
I painted the rest of my Pro Vee with Interlux Pre-Kote primer and two coats of Interlux Brightside, a one-part polyurethane topcoat. I am quite happy with the results (I'm not much of a painter), and would likely go this way again. Of course, there are lots of other choices out there. (Including taking your boat to a professional painter.)
If you have spray equipment, then you will likely want to go that way. I used the roll-and-tip method: apply the paint with a roller, one or two square feet at a time, then tip it off with a dry brush. I used a foam roller, cut in half. A full-length roller would be difficult to use in some places, particularly the coaming where it would barely fit between the deck and the molding.
Roll/spread your coats as thin as possible; this stuff is prone to sag.
Give the primer a pretty good sanding. And sand lightly, but thoroughly after the first top coat. After sanding, vacuum the surface then wipe down with a cloth dampened with mineral spirits. I didn't sand the final coat at all.
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