CPP problems on the navigating bridge
In September 2012 we blogged about ship blackouts due to the use of shaft generators while manoeuvring in port and the December 2012 issue of ‘Shipping Regulations and Guidance’ will focus on this problem.
However, a related machinery failure that often results in a ship grounding or an incident in confined waterways, is any fault that concerns a controllable pitch propeller (CPP) system.
The December issue will have an in-depth article on CPP failures related to automation failures, with checklists on:
- Main causes of CPP faults that are electrically related
- main causes of CPP faults that are related to hydraulic components
- main causes of CPP faults that are related to human error
- measures to reduce the number of CPP breakdowns.
CPP problems on the navigating bridge typically concern one of two circumstances:
1. Deck officers with no knowledge of the setting that the propeller blades will adopt in the event of loss of power to the CPP system.
The default setting that CPPs adopt in the event of loss of power ranges from: Full open, last requested setting, zero pitch and full astern.
On ships that are fitted with CPP, there should be a notice mounted beside the telegraph to indicate the pitch setting the blades will adopt in the event of loss of power.
2. Grounding reports of ships fitted with CPP often refer to the transfer of CPP to the bridge wings (particularly when going into locks when there is little time to correct this). Typically, after switching the pitch control to the bridge wings, nothing happens when the Captain/Pilot goes to the wing and tries to manoeuvre. This situation often creats short period of confusion and frantic calls to the engine room and it is only once they have collided with the dock wall does anyone realise that the switch was broken, the fuse had failed, the levers were not aligned, or similar.