Fuels and Lubricants

Analysis services – helping to get it right


Malcolm Latarche
Malcolm Latarche
ShipInsight

27 June 2019

Analysis services – helping to get it right

Ensuring that engine lubrication is being properly managed is essential for both safe operation and economic reasons. Mostly this is the province of the chief engineer but at a time when many fuels and lubes are produced in quite different ways than used to be the case, some help for the engineer is essential.

There are regular reports of poor quality and even dangerous fuels being supplied to ships and this is the first area where checking is needed. Analyses of engine lubricants can reveal the condition of components within the engine and help predict developing problems inside the engine itself.

The cylinder lubricant in two-strokes is not retained in the engine as it is consumed in the combustion process but system oils from all marine engines and cooling and lubricating moving components can also be used as a means of ascertaining the health of an engine. Proper analysis of the in-service lubricant can give early warning of possible failures long before an incident occurs, allowing preventative measures to be taken. Several companies and classification societies offer analysis services and it is possible for crew to make tests themselves using proprietary test kits.

Some of the test kits for use on board are quite basic but others are much more advanced and include equipment usually found only in laboratories. As well as chemical tests to identify the presence of elements and compounds in the samples, some of the equipment now available makes use of techniques such as X-Ray fluorescence (XRF) to identify them. Some of the onboard systems will also be able to advise on feed rates for lubricants to improve their performance.

Used and waste lubricating oils also pose a problem with regards to their disposal and unless some means of reducing their volume is available on board there will inevitably be a large cost involved for disposal ashore.

A 2015 report from The Swedish Club shows that incorrect maintenance and repair continues to be the most frequent cause of main engine damage – a trend which has continued unabated since the club began monitoring the issue over a decade ago. With an average cost per claim of $926,000, lubrication failure is still the costliest cause of damage to the main engine, due to consequential damage to expensive parts such as crankshafts, pistons and the like.

According to the club, the root causes include crew with insufficient experience and training; experts not in attendance at major overhauls; contaminated lubrication oil and contaminated bunkers.

Implementing a condition monitoring programme to monitor the performance of the engine and cylinder oil is crucial to good ship operation. This programme should monitor the parameters of iron wear and the residual Total Base Number (TBN) in scrape-down oil.

Different components of an engine are made from different metals and minute particles find their way into the oil as they wear. The scrape-down oil from the cylinders shows up wear in rings and liners as well as giving clues to the combustion process, while circulating oil can carry traces of bearing wear from the crankshaft and connecting rods.

Analysis of scrape-down oil can sometimes show evidence of over-lubrication and suggest adjustments can be made to the feed rate to reduce consumption of lubricant as well as preventing fouling of turbochargers, valves etc. As well as showing evidence of engine wear, analysing lube oils also gives information on the quality of the oil itself.

Lubricants break down gradually and their effectiveness reduces as it does so. Topping up is necessary at times but if continued for very long periods can actually result in increased consumption because all of the work of the oil is being done by just a small amount of fresh oil while the remainder may be practically useless. Changing the circulating oil in any marine engine is an expensive task because of the quantities involved so is undertaken only when strictly necessary.

As with machinery components, changing at set intervals is normal practice but this could result in product that has a significant amount of ‘life’ remaining being sent to the waste tank. Regular analysis will reveal what the true quality of the oil is and can mean changes can be postponed for significant time periods.

Almost every major lubricant producer runs a testing and analysis service and there are also several independent service providers. Engine makers are also becoming more involved and providing varying degrees of assistance from monitoring through to complete engine management.