- Sketch of Rudder Modification
One of my more successful modifications has been to add an area ahead of the pivot line defined by the hinges. Unmodified, the helmsperson has to provide all the force to opppose the water running past the rudder surface. Admittedly the length of the tiller arm helps, but I was finding it taking more force than I wanted to come about for a tack.
Since the rudder was built out of fiberglass-covered plywood, it was a simple matter to add some area ahead of the pivot to have the water push the forward area of the rudder in the direction of the tiller, getting the water to aid the effort. Making the forward area about 1/3 that of the part behing seems to wour well. Of course the pivots must be strong enough, and there must be enough clearance to lift the rudder enough to slide down over the pins.
An extra benefit of the forward area and reduced force is the reduced load if an autopilot is added. Less force results in less battery drain.
This modification will not work for a rudder which is attached to a skeg or keel (a fixed surface ahead of the rudder which can protection the rudder when going aground)–the hinges are then attached along the underwater part of the surface so there is no place to have a surface ahead of the hinges.