Damage of main engine crankshaft and the importance of the Planned Maintenance System


Published: 8 February 2024

Credit to: Igor Hotinsky / Shutterstock.com

Over the years, we have seen many incidents regarding damage to main engine components such as the crankshaft, main bearing, and other components of the main engine. The main engine damage claims are one of the most expensive claims.

The causation is often down to poor lube oil quality, and as per the lube oil analysis reports, it is often found that the lube oil has high levels of insolubles and the presence of contaminants. We also see damage to the crankshaft that may be attributed to an in-service material failure and which subsequently damages other major components during normal operation of the main engine. We have also seen in some cases that the engine maker's maintenance and operation guidelines are not being followed.

Skuld wants to highlight the importance of having all main engine maintenance and overhauling to be included in the PMS (Planned Maintenance System). There are cases we see where the damage happened shortly after the overhaul carried out by the ship's crew or shore staff and we therefore recommend that our members follow the maker's maintenance and operation instruction. The vessel should always have the latest versions of maintenance and overhauling instructions from the maker available onboard. We would also emphasise the importance of having the correct knowledge and experience with the engine crew, and they should know all the relevant instructions and guidelines regarding the correct operation and maintenance of the engine.

With the lessons that we learned from cases of main engine crankshaft damage, Skuld's Loss Prevention department would like to advise its members as follows:

  • Lubricating oil should be cleaned using continuous lube oil purifiers with the correct recommended temperature.
  • Lube oil filters should be as clean as possible, and frequent routine cleaning as per PMS should be carried out.
  • Samples of lubricating oil should be sent to a recommended lube oil laboratory for analysis at least every three months or as per company PMS.
  • Lube oil purifiers onboard should be tested for proper functionality and must be operated as per manufacturers' instructions.
  • It is recommended to carry out regular crankcase inspections and crankshaft deflection tests as per company PMS.
  • It is recommended that during major overhauling of the main engine, a maker technician or specialist should be onboard.


Damaged main engine crankshaft removed from the bed plate.

New main engine crankshaft being fitted to the main engine.