We are less than a year apart from the implementation of low-sulfur regulation, however there are still contradicting opinions around the impact that the compliant fuels may have to the various engine types. Despite the fact that various testings are under progress, the results are not communicated among the stakeholders, while no-one really knows what will happen in real life if vessels consume low sulfur oil continuously and not only for a few weeks or months.
Engine developers still argue on the possible impact of the new bunkers on their engines and this is mainly because of the fact that the various engine types may react differently to the new low-sulfur oils. MAN Energy Solutions and WinGD, two leading engine developers, design their engines based on different principals: MAN’s strategy focuses on causing controlled wear to its engines, while, on the other hand, WinGD focuses on eliminating any wear.
As a result, MAN has expressed the opinion that 0.50% sulfur fuels may have a negative impact on its engines since they are less corrosive than the conventional ones and therefore may result into less wear than the desired. For this reason, MAN has suggested Shipowners to replace the conventional cast-iron piston rings with ceramic-metal pistol rings, which will allow the required wear to take place. Furthermore, MAN has also suggested the use of lubricants with higher basicity, in order to avoid piston ring and cylinder scuffing, which, MAN believes, it looks possible to happen with the use of the new low-sulfur bunkers.
On the other hand, WinGD shares a different opinion. It believes that the new bunkers will not have any negative impact on its engines. Unlike MAN Energy, WinGD notes that wear is not needed at all and since its engines are not designed to work with a controlled-wear, they are not going to face any negative impact due to the lower corrosion, the company says. Furthermore, WinGD believes that low-sulfur fuels will not lead to cylinder scuffing. According to WinGD, it is already monitoring multiple engines which operate long term on low-sulfur fuel within SECA Zones and they do not experience any negative issues.
Chris-Marine, an engine care specialist has expressed the opinion that the impact of low-sulfur oils on engines will fall between the arguments of those two major developers. According to Chris-Marine, low-sulfur fuels may have the worst impact on older engines that are less corrosive than newer models which are characterised by longer stroke and higher firing pressures.