- When 30% to 40% of the area is forward of the turning axis there is no torque on the rudder stock at certain angles.
- At some angle of rudder, it is balanced. i.e., torque is zero, to keep rudder at that angle.
- Axis of rotation lies between 0.2 L and 0.37 L.
- Semi-balanced rudder
- A rudder with a small part of its area, less than 20%, forward of the turning axis.
- At no angle rudder is balanced.
- Axis of rotation lies less than 0.2 L.
- Unbalanced rudder
- A rudder with all of its area aft of the turning axis.
- At no angle rudder is balanced.
- Axis of rotation is the leading edge.
