Measures to be taken against ships power supply failure
Onboard ship a power failure might occur when the generation or distribution of power is dysfunctional resulting in blackout. In critical ship manoeuvering time if such failure occur it resulted in a huge consequence. Collision, contact damage with a shore structure or running aground are example of some worst power failure cases. Depending on circumstances, however, if power can be restored immediately a ship may avert such a disaster. But there involve some complexities that need to be properly addressed for restoring ships power. Master and chief engineer need to apply best judgement in a power failure situation to ensure ship safety and organize crew to put their best efforts. Summarized below some power failure cases and recommended guideline for ship staff.
Case 1 : Power supply can be restored quickly by Standby Generator
When the running generators fail to supply Electricity, the standby diesel generator(s) starts. Provided that the voltage and frequency have settled, ACB (Air Circuit Breaker) turns on, and electricity supply is restored automatically to essential machinery and equipment one after another.
The Master should take command on the Bridge and pay due attention to any converging traffic, or obstacles in the vicinity and the sea and weather conditions. He should call extra officers to assist and confirm:-
That attention is drawn from the other vessels in the vicinity, and the traffic control center (if applicable) by VHF, whistle, signals that its vessel is 'Not Under Command.'
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Ships position
- Status of M/E;
- Speed of the vessel;
- Ships headings (both gyro and magnetic), and the operating condition of the Gyro-compass;
- Status of steering gear (manual steering should be considered when necessary),
- Radar operating condition
(when S/B lamp is off, Turn switch to S/B position and start warming up);
- Other navigational equipments operating condition;
- Operational condition of radio equipment;
The chief engineer should instruct the Engineer on Watch and call additional Engineers to check and operate the following: -
To confirm that Essential machinery has started Automatically;
- To check if Electricity for Navigational equipment is sufficient and secured;
- To start M/E again on confirmation that the ship is ready for Navigation after checking M/E and operating condition of navigational equipment;
- To reset selective-trip mode NFB (Non Fuse Breaker) in the distribution box.
Especially NFB for reefer-container power supply has to be reset immediately, and the operating condition of each reefer container shall be checked;
- Air conditioning machine, Refrigerating machines, Purifiers, and such other equipment which do not directly participate in the ship's operation shall be started Manually since they are not equipped with Automatic starting system.
Case 2 : Power recovery Cannot be done Immediately
In case the Stand-by Diesel generator fails its automatic start or its voltage and
Frequency does not settle; Emergency generator starts automatically, provided that its voltage and frequency settles, then ACB turns on, and starts to supply Electricity to the following essential machinery:-
Steering gear system;
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Emergency lighting system;
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Radio equipment;
- Navigational instruments;
- Engine monitoring console and M/E control system, and
- Elevator and etc.
The Master should take command on the Bridge, and he takes necessary measures below mentioned: -
The steering gear is supplied with Electricity and vessel on Manual steering;
- Gyro compass is supplied with Electricity and is in good operating condition, then check and note the difference between Gyro heading and Magnetic heading;
- Fix ships position successively, check drift and prepare to anchor if possible
- Confirm power supply for each navigational instrument and check their operating condition.
Chief Engineer, on confirming power supply from the emergency generator is secured, he takes necessary measures below mentioned: -
Check if the power supply is restored to the Most Crucial Machinery;
- Check operating condition of the Emergency generator, especially that the Damper device of Cooling Fan is in opened condition (if applicable)
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Investigate the causes of both the Generator failure and the Stand-by Generator failure to start. Try start Main Generator again.
Case 3 : Power Failure during Berthing or Un-berthing
A power failure during berthing or un-berthing will render the Mooring Equipment and Bow thruster unavailable due to their considerable electric consumption.
The operation should be aborted, and Tug assistance to be requested to tow the vessel to an anchoring position where investigations, repairs, and further testing can be carried out.
Case 4 : Power Supply Failure during Cargo Handling
(Tankers and Gas carriers)
Possibly power supply by standby main generator(s) might be insufficient for running electromotive equipment or machinery such as Boilers, Inerting system, Cargo pumps, Re-liquefying plant, Ballast pumps, etc.
The officer on Watch shall report the power failure to the Chief Officer and Engineer on duty, summon other officers for help and carry out the following:-
Instruct deck watch crew to confirm operating condition of both ESD (Emergency Shut Down) valves (when ESDS is fitted) at the Manifold, and Shoreside ERS (Emergency Release System),
- Inform terminal representative without delay of the stoppage of cargo handling due to power failure.
- Confirm all valves condition (open/shut) then take proper measures to prevent liquid movement and liquid blocking in both cargo lines and ballast lines.
- When the power supply is recovered by Emergency generator or S/B generator, check conditions of cargo equipment, then take such measures to handle concerned valves to prevent to the rise of the inner pressure of tanks.
When the power supply is recovered back to normal and sufficient for cargo handling, Chief Officer should after checking the operating condition of cargo equipment and consulting with the terminal representative, resume cargo operation.
Engineer on duty shall immediately report the power failure to the Chief Engineer or First Engineer, and then endeavor to supply required power by starting generator(s) that provides Electricity sufficient for cargo handling or by restoring and starting the failed generator(s).
Operational checks for ship equipments
When the power supply is restored operational test and status of all navigational equipment, radio equipment, including gyro compass, should be checked. Inside the engine room, all engine monitoring console and M/E control systems need to be checked immediately. If power was down only for a short time, there might be negligible effect expected on essential machinery and equipment since they are fed with ships back up battery (DC 24V) or built-in back-up battery.
Resetting of equipment should be carried out as required.
Countermeasures, long running of main generator unavailable-
Air outlet valve of the reservoir should be appropriately shut to preserve starting air for the main generator, and
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Power supply from the Emergency generator should be kept at minimum required equipment if fuel on hand for the emergency generator is insufficient.
Note:
It shall be noted that heat-up on the Emergency generator during a long time run may abort power supply, even its fuel remaining.
Countermeasures, long running of both main generator and emergency generator unavailable-
Limit power supply from ships back-up battery (24v DC) and prevent electric discharge from the same.
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Air outlet valve of the reservoir should be shut properly to preserve starting air for both the main generator and emergency generator
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