M_Boats: Revarnish rudder?

Hello, The varnish on my M-17 rudder is starting to peel off, especially at the leading edge. Did anyone here revarnish theirs? Do I need to remove the old varnish first and then recoat it? What materials have people used? How many coats are needed? The rudder will spend its time out of the water when boat is not sailed. Thanks, Andrei.