(In my quest to keep the twenty-somethings in sight until at least the second turn) Can an epoxy film be polished to as smooth a finish as varnish? Or, can paint be polished smoother? I like the idea of keeping the bottom of the boat epoxy-only, for easy repairs and refinishes, but will give that up if there is a better choice.

Perhaps the fashion has changed, but when I was around the 'go fast' (marathon canoe, sailing dinghy) crowds, the preferred hull treatment was wet sanding with 320 or 400 grit - a nice dull and smooth finish (vs. high gloss).

You can get (aged) epoxy sanded to a very smooth finish, and with rubbing compound you can bring up a bit of gloss. Depending on the temperature, it can take quite a while to get epoxy (or varnish) hard enough to rub out to a good gloss.