Castrol Marine believes owners can maximise performance and safety on their cruise ships by using higher BN cylinder lubricants when slow steaming.
While lower 40 BN cylinder oil suits vessels operating mainly in Emission Control Areas (ECA), 70 BN and higher lubricants are better suited to vessels which are regularly slow steaming, so that piston ring packs and liners remain in excellent condition, Castrol maintains.
The company's marine and energy lubricrants technology manager Paul Harrold said: “Replacing liners on a 14-cylinder engine could cost over US$1 million. Higher BN lubricants provide greater neutralisation and hence better corrosion protection across the fuel sulphur range while slow steaming. The idea of a single, mid-range cylinder oil solution for all vessels as sulphur limits are reduced may be seductive, but our field evaluation shows this does not offer the best margin of safety.”
Based on its own engine performance tests and OEM reports, Castrol believes offering a choice of cylinder oils is essential for performance, with its investigations showing that each vessel should use a cylinder lubricant based on its predominant operating conditions.
While the company recommends a 40 BN lubricant for prolonged operations in ECA, a 70 BN cylinder oil for intermittent ECA operation and 80 BN for slow steaming, it believes most ships will carry just one.
Mr Harrold said: “We are not suggesting that a ship has to carry a range of products. In fact, the majority will carry only one, depending on their engine and voyage operating pattern. Our position is that only by having a comprehensive range of cylinder lubricants to choose from, can vessel operators maximise machinery performance and provide the highest margin of safety."
Castrol intends adding an 80 BN option to its cylinder oils range.