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A new marine engineer may need to learn several things on their own, since not everything can be taught at the marine school in a practical manner. Some of these things might seem very simple but could be quite confusing for a trainee engineer. So I thought of penning down my experiences of watch keeping and hence will continue in the next few articles along the same line
The purpose of these articles is to inform newbie engineers about the watch keeping duties of an engineer at sea in charge of a marine diesel engine and will include the following:-
- Engine-room layout
- Main engine components subject to pressure and temperature change
- The reason or cause of a rise or fall in temperature to an engine-room item of machinery
- The consequences of these changes in pressure and temperature on the diesel engine efficiency
- The rectification of a rise or fall in temperature or pressure
- The affect a rise or fall has on various cooling and lubricating liquids
Certainly it is not possible to indulge in all these in a single article as that would be an impractical idea so will proceed step by step and will start by talking about the standard temperature and pressure checks to be performed during a watch. Before I proceed with that, I would like to suggest another article about basics of marine watch keeping that will give you a broad idea about the entire concept in case you are not familiar with it.
The next sections detail the checks to be carried out by the engineer regarding standard temperatures and pressures of various components, and what we are looking for during the checks.
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Standard Pressure and Temperature Checks
There are standard pressures and temperature checks to be carried out by the watch keeping engineer, as he gains experience these will become second nature; the various thermometers and pressure gauges being scanned as he walks around the engine room checking the components. This means when a rouge value turns up it is spotted right away either on the component or the engine control station instrument board. This is situated just above the engine control station, either in the engine room or in the modern control room. The board contains the pressure and temperature gauges for the main systems such as; exhaust temperatures, jacket cooling and lub-oil pressure. We used an arrow to mark the optimum temperatures and pressures on these gauges, and endeavor to maintain them; again any rouge value will show up instantly.
The board is located above the controls, being easily consulted from here. The other main gauges and components that are easily reached are the engine room telegraph, rev-counter, air start reservoirs pressure gauges and of course the controls themselves. Depending on the engine manufacturer, these consist of two levers; left hand one usually air start, right hand lever; fuel control and are used when maneuvering.
A sketch of an engine room control station and board is shown below, please click on image to enlarge;
Heavy Fuel Oil System (HFO)
The temperature of the HFO system must be kept at the recommended value to control its viscosity. This is important as it must not turn "waxy" when being pumped through various heaters, the fuel pump and into the injectors.
The temperature of the lube-oil must be carefully controlled through use of the lube-oil coolers seawater inlet valve. Remember that as the temperature of the lube-oil rises the pressure drops. Conversely, a low lube –oil temperature will increase the oil pressure. A sudden unexplained rise in temperature could signify a bearing in the main engine running hot.
Jacket cooling System
The pressure and temperature of the jacket water cooling also need close monitoring and maintained at optimum values as the cooling water also supplies the turbo-blower air coolers. The pressure in this case is controlled by the circ pump, so any change could be a faulty pump, however, down to the pump or a loss of pressure through a faulty cylinder liner rubber sealing ring, or even a cracked liner.
Temperature is another matter; this must be kept at the recommended value. Any rise could signify a scavenge fire a rise in sea temperature or cooler problem.
The generators temperature and pressures are checked as per the main engine ones.
This leave the thrust block, prop shaft bearings, and stern gland. Here again the sense of touch should be used as a guide to overheating, but there will be temperature gauges on the thrust and prop bearings along with oil - level sight gauges.
In my next article I will continue along the same vein; talking more about these subjects and catch hold of another single aspect in more detail. So just keep a look out for my further articles and please ask any questions through the comments at the end of the article. Enjoy your time at sea – it is the best years of your life.