Submarine manoeuvring and appendage design - what is the best option for a large SSK?

<p>In order to control manoeuvring motion in both the vertical and horizontal planes submarines are fitted with controllable appendages. The traditional approach to this for modern submarines is a rudder to control motion in the horizontal plane, together with forward and aft planes to control motion in the vertical plane.</p> <p>The differences in manoeuvring in the horizontal plane and the vertical plane are outlined, and the need for forward planes demonstrated. There are various options for the location of the forward planes, and the pros and cons of these for a modern SSK are discussed.</p> Many SSKs are being fitted with X planes instead of the traditional cruciform configuration of rudder and aft planes. For some submarines X planes are likely to be better options, whereas for others the traditional cruciform arrangement is preferable. The hydrodynamic differences in the way these provide the required forces to control manoeuvring in both planes are explained, and the advantages and disadvantages of the different arrangements are discussed.