Oil supplier expresses concerns over high or low BN cylinder oil choice

The French marine lubricant supplier agrees that general operations for two-stroke diesel engines are becoming more severe, increasing the technical challenges required for deposit control, cleanliness and wear protection. However over the past decade, conventional MCL wisdom has changed and Total believes that it has been proven that the BN argument is now outdated. This is because BN alone is simply not enough to explain the neutralisation performance of a lubricant. As such, Total Lubmarine states that the implications of this ‘high BN with conventional chemistry’ approach are at best risky and at worst dangerous.

Jean-Philippe Roman, technical director, explained: “It is important to note that it is not the level of basicity that is dangerous, but the underlying chemistry with which products are formulated. For anyone relying upon the conventional MCL chemistry – which the majority of lubricant suppliers now recognise as outdated – it is understandable that the only option is to increase the BN. However this presents a high-risk strategy; too low a BN for the sulphur content can lead to acid corrosion of the liners, whilst too high a BN can lead to hard calcium deposits and an increased risk of bore polishing and liner scuffing.”

Lubmarine believes that suggestions that ships choosing a high or low BN lubricant based upon their predominant operating patterns will only have to carry one cylinder oil is not only restrictive but also potentially dangerous. Without a back up providing the option to switch between high and low sulphur fuels and corresponding MCLs, certain route changes would prove impossible and operational safety could be compromised.

Total Lubmarine agrees that any new cylinder lubricant launched to the market must be tested in all extremes, and not just in the conditions that suit the product. With more than 2,000 samples from slow steaming vessels, Total Lubmarine can attest that the iron measured in the drain oil – which denotes engine wear – is lower with its newest multipurpose MCL than with a conventional mid- or high-BN lubricant.

Roman explained: “New industry realities require new thinking from MCL suppliers. Single oil solutions may represent a paradigm shift for the industry but they are also a break-through in product applicability for shipowners and operators facing unprecedented economic and environmental challenges. Universal lubricants are conclusively proven to meet vessel needs in all operating conditions, so whether slow steaming or transiting ECAs, all of our customers can operate in the knowledge they are not risking damage to their engine.”