CPP systems are used in various merchant vessels. They have advantage of good maneuverability. But if this system fails, then it might create lot of problems. In many ships having this arrangement steering gear is not present. So, if it fails then it is very difficult to steer the ship.
CPP system uses the hydraulic oil to change the direction of the blades. Since we can change the direction of blades, a good propulsive and steering capability is experienced by the ship. Although in bigger ships they have not yet been used much, but in small vessels, they are of great use and used there in maximum numbers.
Controllable Pitch Propeller System
If Controllable Pitch Propeller System fails, First Follow manual mode on local or use it as fixed propeller. Actually this will depend on what kind of control system you have onboard. Your CPP has a fail safe system if due to any failure or leakage you are not able to change pitch it will automatically lock itself in forward direction. At this time RPM has to be reduced as it might affect the steering capability of the ship. Switch of the hydraulic pumps for this system.
If hydraulic system has failed, Pitch will change to either full ahead or full astern. There is fail safe arrangement whatever be the situation in the event of failure of system the spring force will push the ram controlling the pitch of blade in ahead direction and in that case if you want to use reverse movement of engine then you have to make adjustments with the engine . Some engine may have this kind of arrangements.
In one of the systems in which they had provided an emergency local control. Which consisted of a lever indicating the pitch. Bridge would give the command you acknowledge and move the lever to the desired pitch. It is something similar to local engine side control for fixed pitch propellers.
There is fail safe arrangement whatever be the situation in the event of failure of system the spring force will push the ram controlling the pitch of blade in ahead direction. Hence you can move in ahead direction only because normally reversible engines are not used. When you reach within Port limits you will have tug assistance.