One of the most important qualities that a marine engineer must have is to know and understand his machinery extremely well. Before breaking down completely, each machinery will show a variety of signs and symptoms indicating the type and severity of fault.
Along with knowing the right procedures to operate ship’s machinery, mariners must also know how to identify and troubleshoot any problem in the engine room.
Following are 10 ways in which a mariner can identify and rectify a faulty machinery:
1. Abnormal Sound
Sound is by far the most prominent factor which draws seafarer’s attention towards a troubled part or machinery. If you are a good watch keeper, it will be easy to figure out the difference between normal running sound and problematic sound even when you are not near of the machinery. For e.g. A “hissing” sound will indicate leakage, a loud knocking sound will indicate loosen or broken parts, a high wobbling sound will indicate obstruction etc. Unfortunately there is no guide to learn these sounds. Only through experience can one master such skills.
Another powerful indication, which can be easily detected by human senses, is that of abnormal smell coming from machinery or systems. When you sense heavy/strong smell in the vicinity, it can be due to leakage of oil, fire, effects of high temperature etc. A burning smell near the motor is an indication of increase in temperature of its coil. You can detect the smell of heavy oil even if you are not able to see it. Similarly, steam leakage will leave a dampen smell. It’s only while working on board ships, one is able to know and understand different smells indicating a variety of problems with the machinery.
3. High Vibration
All machinery systems with moving parts generate vibration. One of the most neglected maintenance jobs for machinery onboard ships is that of vibration analysis. Many shipping companies do not include it in its planned maintenance system. Even the timely checks for tightening the foundation bolts for any machinery are not included in the PMS. Every machinery will have its own frequency of vibrations. It is important to keep a track of any increase in the vibration of machinery, which if ignored, can lead to severe damages in the long run. Any change is vibration of a machinery can easily be felt on board ships. This is a sign which should never be ignored.
Leakages are a result of faulty piping or machinery systems. They are easy to identify on board ships. Never ignore leakage from any kind of machinery as it can lead to spills, fire, flooding and other major accidents. If you find oil water or air leak in the machinery, do try to rectify it immediately or mark it as important to check during next maintenance schedule depending on its severity.
Every machinery with a combustion chamber can be judged for its performance by checking the exhaust smoke for its color and density. Exhaust smoke of Main Engine, Auxiliary Engine, boiler etc. to be monitored for knowing the combustion process. A black smoke indicates a problem in fuel injection system and improper combustion (lack of air etc.) whereas white smoke indicates water ingress in fuel.
6. Abnormal Parameters
Abnormal or fluctuating parameters are mainly related to machinery faults. It’s important to keep a track of all machinery parameters on board ships by comparing the readings in the log book to the data of previous dates. While taking a rounds, any deviation in the parameters must be taken seriously by taking proper investigation and preventive actions.
Every alarm indicates a problem, major or minor, on board ships. They have been installed for that purpose of identifying faults. Never ignore an alarm related to any kind of machinery. An oil mist detector alarm in the main or auxiliary engine, even when other parameters are normal (Crankcase temperature, scavenge temperature etc.), must be taken seriously. Many incidents has been reported for crank case explosion when OMD alarm has sounded but the crew ignored it seeing other parameters are normal.
8. Observing Problems in Connected Systems
In ship’s engine room, most of the systems are connected to any other form of system or machinery. If a problem is observed in one system, do check the other machinery connected to it. For e.g. When there is a problem in the expansion tank level suddenly going down, do check any leakage in the main engine, generator, or air compressor connected to it. A leakage in jacket water of the engine will lead to air going into the expansion tank with high pressure during compression stroke and emptying the expansion tank from vent or other openings.
9. Change in Amperage
More than 80% of the machinery on a cargo ship are electrically operated i.e. from ship’s generated power. Ensure to check the current of all the electrical operated machinery and pumping systems. A high current for a purifier indicates problem in the clutch drum or transmission gear. Similarly, high auxiliary blower current indicates the scavenge pressure inside the engine is more than that supplied by the fan. Since in most ships, the auxiliary blower fans are operated manually, the fan must be switched off when the pressure is reached or when the current crosses the marked limit.
10. Knowing Your Machinery Inside-Out
Last but not the least, knowing your designated machinery inside-out will help you identify the minutest change in its performance. Learning about its history, reading its maintenance reports, and keeping routine checks will give you an idea as to how your machinery acts and performs under different conditions. This would make it easy for you to recognize any fault in your machinery system when it operates different from its usual working pattern.
Identifying machinery faults is an art which comes with practice and experience. Do you know any other important methods to identify machinery problems?