A blackout is an unexpected loss of electricity and it is a very rare and unusual thing to happen, especially if you are in the engine room and have never experience it before. It gets very dark and quiet all of a sudden, though some diesel engines may still be running as the fuel will be supplied by gravity to these engines.
Vessel automation is installed to protect us from these kinds of unexpected things, therefore Power Management Systems (PMS), preferential tripping of non-essential machinery, and sequential start systems help us get going again automatically. This, however, has a side effect as engineers are getting so used and complacent to “the system” taking care of us that they no longer know how to recover after a blackout.
When a blackout happens, you should stay calm as usually the emergency generator should start within 45 seconds and give you back the essential minimum services you need in order to recover.
The alarm and monitoring system are normally continuously working as they are supplied, for safety reasons, from vessel batteries (you can read more about these if you follow this link).
As soon as you can, you need to inform the Officer of the Watch on the bridge about what is going on and try to be as accurate as possible. Take the main engine control into ECR and move the control lever back to the stop position so that you can re-start the engine later in an orderly way.
If the engineer’s alarm hasn’t gone off yet, turn it on now and call the Chief Engineer.
Most of the time, the main engine will have stopped because the electrically driven lubricating oil, fresh water, and sea water pumps have stopped working. If the auxiliary boiler was running, close the main steam stop valve to preserve the steam pressure. and once engineers have reached the engine room and you have enough manpower available it might be a good idea to stop using steam for non-essential services (like accommodation heating, fuel tanks heating, etc), as this will make it easier to get steam pressure quickly back to the fuel oil heaters, which are needed to power back and move the vessel.
It is a good idea to record these things (usually on the whiteboard inside ECR) so that everything can be put back to normal later.
Meanwhile you should try to figure out why the power went out, and the data logger might give us some clues about the events that lead to the blackout.
Once the cause of blackout has been found it needs to be fixed, if possible, or isolate the faulty equipment that might be causing it.
During a blackout there is a lot to do and everything should be done in an organized fashion, therefore a recovery procedure should be in place, which can guide you through the whole situation, with specific task delegated to engine crew members.
On most ships, but not all, we can’t run the main generator and the emergency generator at the same time. We can usually get them to work together, but there are usually two circuit breakers (bus tie breaker and emergency generator breaker) that are set up so that only one can be turned off at a time.
This means that we can use either the main switchboard or the emergency generator to power the emergency switchboard. There is no way that we can’t use the emergency generator to power the main switchboard. So now in case of a black out and automatic start of emergency generator, the emergency switchboard will usually be powered by the emergency generator and the main switchboard will be powered by the main generator with no link between the two.
At some point, after everything is more or less restored, we’ll have to link the main and emergency switchboards back together, which means putting power back into the emergency switchboard from the main switchboard. Normally this operation happens automatically as the tie breaker will close once there is power from the main generator and the emergency generator breaker will open and it will automatically stop.
If this system works then it is great, but if don’t then everything should be manually restored. During manual operation you should keep in mind that anything fed from the emergency switchboard will lose power for a short time and it is important to know what this affects, because it could cause another blackout (for instance, if it is supplying power to the main generator fuel pump). During this change over, essential navigation equipment is usually kept running with the help of individual Uninterruptible Power Supplies (UPS) (you can read more about these if you follow this link).
Restoring the manually the power should not be a problem for an engineer, since we do this operation as a routine weekly exercise when we test the emergency generator on load.
It is important to note that after connecting the main switchboard to the emergency switchboard again you need to turn off the emergency generator. There have been many times when the emergency generator was left running after the power has been recovered. Also, make sure that all of the controls are back to “Auto” and ready to go for the next time.
Now that we have enough power, reset the breakers and turn on all the other machines and systems that need to be on and breakers in the preferential tripping sequence are among these (non-essential machinery). On container vessels which carry large amount of reefer containers and where the energy demand is very high, you need to ensure that reefer breakers are started in an appropriate manner, one by one, in order to avoid main generator overload which can cause another power loss.
Modern power management systems make it less likely for power to go out for no reason, but engineers must be familiar with the specific procedures, where to find the instructions and procedures, and ready to act in case of automation failure.
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