Advantages of Controllable Pitch Propeller (CPP) are -
(a) Immediate control of the vessel by the OOW. (b) The ship can be stopped, without stopping the engine. (c) Shaft alternators can be used with a constant speed shaft, thereby saving on the cost of auxiliary fuel for generators. (d) Air start bottles are unlikely to cause a problem during continuous manoeuvres. (e) Bridge wing and central control positions provide better ship handling.