Centerboard trunk cap refinishing

I'm refinishing the centerboard trunk cap. At the one end (centerboard opening/front) there is a crack that is about 4" long and at most 1mm (1/32") wide. The crack doesn't seem to impede the sturdiness so I'm thinking of reusing the wood. Should I use a filler to fill the crack before refinishing it or will the sealer and varnish fill it? I'll be using Interlux Inter-Prime Sealer #1026 and Z-Spar #2015 Flagship Varnish for the refinish.

Claus FS5074 Ames, IA

Assuming you are totally stripping the wood, and perhaps restaining, I would fill the crack with epoxy and microspheres which often come in a brown color so it blends in well. Don't bother with the sealer(unless you already purchased it), just dilute the initial coats of varnish with thinner. First coat 50% thinner, second coat 25% thinner, thereafter 5-10% thinner depending on weather, RH, etc. I refinish mahogan runabouts for a living. Paul