Several cases of scuffing, excessive wear of cylinder liners as well as the wear, sticking or breakage of piston rings, and deposit formations in the piston crown and ring areas of two-stroke main engines have been reported since the global use of very low sulphur fuel oil with max. 0.5% sulphur (VLSFO) began on 1 January 2020. Figure 1 shows a scuffed liner and Figure 2 shows deposit build up on piston lands.

Along with information on the characteristics of VLSFOs that the Society has investigated to date, this TEC also provides information on possible measures which can be taken to prevent the above-mentioned damage; therefore, please conduct the following recommended scavenge port inspections and cylinder drain total iron analyses as necessary.

Although the characteristics of VLSFOs tend to vary to a greater degree than the characteristics of traditional high sulphur fuel oils (HSFOs), samples of the VLSFOs that the Society has investigated to date were confirmed to conform to the specifications of ISO 8217. Table 1 shows the characteristics of some of these samples.

(To be continued)