The rudder was in bad shape. Completely saturated with water. You can see were some previous owner drilled random holes to drain. Their patch job eventually leaked as well. I dug a hole in the ground and dropped the rudder out to work on in the garage. I sanded down to the gelcoat and drilled 5/16 holes every 3x3 inches. Then i let the core dry out for about 2 months, refilled with penetrating epoxy. Put 4 cotes of barrier paint back on and bottom painted.