The sole should not get wet!!
I made new soles out of birch ply, stained light oak and grooved on the table saw. I filled the grooves with mahogany wood filler in a tube from Home Depot. Apply a first coat of varnish before applying the filler so that it doesn't creep in the grain. When the filler is dry, sand it flush and then varnish. I used Helmsman Spar satin varnish because I already had it lying around. There is no UV worry in the cabin and it certainly shouldn't get wet under normal use. I built up eight coats with a very light sanding between each coat. Make sure to varnish underneath as well to protect the sole from moisture in the bilge and to make mold removal easy. I leave the boards tilted up when I'm not on the boat so mold doesn't start. (I get moisture in the rear bilge section from heavy rain getting under the companionway slide. The sole is lighter than teak and holly as the main area is light and the stripes are dark, brightening up the cabin into a light and cheery place.It was easy and cheap to do. Oh, BTW, bore 1" finger holes at one end of each section except for the triangular forward piece which gets screwed down