8 Important Points To Note For Maintenance Of Emergency Generators On Ship

Any kind of emergency equipment or system provided onboard is an important lifeline for the ship and its crew when faced with an emergency situation. Emergency Generator is without doubt one of the most important equipment on board, which is responsible for preventing accidents and grounding during power failure while the ship is in heavy traffic, channels, rough weather or in manoeuvring.

The Emergency Generator on ship comes into play as back up source of power when the main generators fails to provide the necessary power to the engine room and other deck machinery systems.

Considering its high importance, the emergency generator is required to be tested regularly along with carrying out all important planned maintenance jobs as per schedule. This would not only ensure smooth running of the emergency generator but would also avoid breakdown when the ship is already facing a distress situation.


Following are some important maintenance jobs that need to be carried out in emergency generators on ships:

1. Change of Engine Sump Oil: It is important to check the oil level in the sump regularly. Since the emergency generator is kept on auto mode, which ensures the generator starts and comes on load automatically, it is necessary that before starting the engine for operation, oil level is checked on regularly basis. The condition of the oil will be known during this period and if the oil is having carbon or soot particles, change of complete oil system needs to be done. The running hours for changing of engine oil depends on the manufacturer, the engine make and the oil grade in use. Normally it is done between 250-500 hrs.

The oil changing period must be cut by half when the fuel used in generator is more than 0.5% to 1% sulfur.

2. Clean Air Cleaner: The combustion air for the engine is passed through an air filter, which can be of following types:

1. oil bath air cleaner

2. dry type air cleaner (cartridge or dust collector).

It is important to clean the air filter at correct intervals of time as delay will lead to clogging and less air going in the engine. This will reduce the efficiency of the engine and increase the thermal parameters. When using dry cartridge, ensure to replace them at intervals stated by the maker. Normal replacement schedule is one year or after 5-7 cleanings.

3. Check Water Separator: Some emergency generators are provided with water separator to prevent mixing of water with fuel. Check the level of water and make sure it is below the marked level and regularly drained off. This is to be done to avoid rust and corrosion of fuel line devices and to avoid incomplete combustion.

4. Check Electrolyte in the Battery: A battery is used in one of the starting methods of the emergency generator. The electrolyte level in the battery must be checked at regular intervals either by inserting a level stick or by checking the water level in the level tester cap (if provided). Use distilled water to make up for the low level.

5. Check Alarms and Shutdowns: All the safety devices and alarms fitted in the emergency generator must be checked and tested regularly. Generator with V-belts have additional alarm which will be sounded in the event of belt failure and operated by idler pulley.


6. Check V belt Tension: When V belt is fitted, inspect the same for cracks and damages. Renew the belt if damage/ cracking appearance is more. To check the belt tension, press the belt by thumb in midway of the pulleys and check the inward deflection in mm. It should not be more than 10-15 mm depending upon the make of the generator.

7. Clean Oil Filter Cartridge: The emergency generator is provided with various oil filters such as by pass filter, centrifuge filter, lube oil filter, fuel feed pump filter etc. These filters need to be cleaned or renewal of filter cartridge is to be carried out as per the maker’s instruction or oil condition.

8. Check Valve Clearance: The tappet clearance of the inlet and exhaust valve should be checked at running hours stated in the maintenance section of the generator’s manual. Also ensure the engine is cold before taking the tappet clearance.

Loss of emergency generators at times when they are needed the most can lead to unfortunate and disastrous incidents. Followed a proper planned maintenance system along with thorough regular checks is the key to ensure smooth running of emergency generators on board ships.

Over to you..

This is not an exhaustive list of important maintenance points. Are you aware of any other point that should be added to this list?

Let’s know in the comments below.

Do you have info to share with us ? Suggest a correction

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About Author

An ardent sailor and a techie, Anish Wankhede has voyaged on a number of ships as a marine engineer officer. He loves multitasking, networking, and troubleshooting. He is the one behind the unique creativity and aesthetics at Marine Insight.

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  1. I would like to add few more points: 1. checking the functioning of the ventilator flaps. The ventilator can be closed from outside the emergency generator room in case of fire.

    2. Check the antifreeze on the cooling water system.

    3. Emergency generator must be test run ON-LOAD at least once in a month for 3-4 hours. During this time the frequency, current, KW produced must be recorded every 30 minutes to ensure proper functioning of the emergency generator.

  2. Anything about the sea-water cooling system and the heat exchanger?

    Very useful article.

  3. Check the hydraulic system for starting manually if the emergency generator is equipped with.

  4. Anish can u tell me how reverse power trip testing is done onboard?
    Also can u guide me how blackout simulation test is done onboard?
    It will be very much helpful

  5. Photos accompanying your articles are taken from Maersk’s Margrethe-class vessels looks like (now G-class) 🙂 …I’ve been sailing on them the past few years. Nice website this!

  6. As per rules/regulations every emergency generator to be fitted with secondary means of starting. It can be another set of battery, hydraulic (accumulator) or pneumatic. Important to be maintained and check to be done at regular intervals.
    Attention to be paid to the level of fuel in the fuel tank. Capacity of fuel tank fixed as per rule and to ensure a min level always maintained.
    Nothing mentioned about maintenance of generator and EMG switch board.
    Another point to mention, this is not mandatory for all emg diesel generators to come into running and connect to the supply circuit automatically. That is depend on the vessel notation.

  7. Very important. First check gas oil tank
    If the emergency g. In close room open. The window or hatch cover. Put the switch in. Position. Outomatic

  8. One critical area overlooked; Fuel integrity. Tank should be topped with minimum head space to avoid condensation – and potential for microbial buildup. If the fuel is in storage more than six months, fuel should be treated with high quality fuel stability additive, especially if the fuel is 0.1% sulfur, as hydro-treated low sulfur fuels tend to degrade rapidly. More than half of emergency generator failures occur as the result of degraded fuel.

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