The tail vertical rudder meter set a vertical gyrocompass to control the vertical tail rudders. Boat rudders may be either outboard or inboard. The aircraft was of all-metal construction except for fabric covering the rudders and ailerons. There are separate upper and lower rudders, and elevons. This rule promoted the use of fin keels and blade rudders. Two semi-balanced rudders were placed behind the two inboard screws. For use when minehunting the vessels have two ACEC active rudders and a bow thruster. The tail rudders and side stabilizers were operated by air pressure. Control is by forward rudders with large rear fins. The C-2 has four vertical stabilizers, of which three are fitted with rudders. This required a single screw aft of the rudders and stern planes. Autopilot systems combine mechanical rudders with navigation systems. Cruising catamarans entail added expense for having two engines and two rudders. Both rudders and lee boards have swiveling tips so the dinghy can be landed. She is fitted with two rudders (which can be individually controlled) as well as stabilizers.