If it's sound , just put a bunch of coats of varnish on it. I find an aresol can of spar varnish allows you to get alot of coats on in a short amount of time.  If it's in bad shape  then strip and start over. If it's delaminated then open cracks and sand then squeeze in epoxy and lightly clamp it. Put a little filler in epoxy if needed. Coat tiller in a few good layers of epoxy, then many coats of varnish

I did mine last fall when I replaced my rudder.  I’ve no idea what kind of wood it is.  Ash?  Maple?  

So, I removed my tiller last fall intending to refinish it this winter/spring. It's now April and pressure's on. :-)

Any guidance on the best way to prep and refinish? Is it similar to refinishing benches, etc? Not sure what type of wood the tiller is made of either. Yonder 1515. Thanks