Action of Rudder in turning a ship and its three phases
We all know every ship has a rudder which helps in turning the ship and is always at the stern of the vessel after propeller. To understand the turning of the ship and how rudder turns the ship, lets assume that the helmsman has given rudder some angle to the starboard side.As soon as the helmsman gives rudder some angle to the stbd side, then at very moment a lift force acts on the rudder which is directed along the traverse direction to the ship in port side. Other than this, the rudder force has another effect on the ship. It creates a moment about the CG of the ship. This direction of the moment will be towards stbd side because of the rudder force is acting about the CG of the ship. When the rudder moment acts about the ship's CG, it slightly changes the ship's orientation by giving it a drift angle. See above figure. The ship with that drift angle is moving along the initial direction.From above fig it can be seen that the ship's velocity has two componen