A hole must also be made for the rectangular rudder head. To do this, first place a piece of masking tape on the deck where the rudder head will emerge to prevent splintering. Start the drilling from the bottom of the hull and continue carefully, following the stern post, up through the deck and masking tape. Now with a flat file, "square" off the hole until the rudder head fits smoothly. Take your time and eventually you will get the desired results. Finally, the rudder coamings are fit and glued. Sand!