If there is one standout cause for failures of main and auxiliary engines, it is through inadequate monitoring and maintenance of the condition of lubricating oil – literally the life-blood of any engine. The American P&I Club has issued a new case study taking into account best practices in the prevention of shipboard machinery failures.
The case study incident:
The medium speed main engine of a bulk carrier suffered a turbocharger failure whilst on transatlantic passage to New York. The engine had then labored for several days with a non-functional turbocharger creating very poor combustion and black exhaust smoke. Whilst in port and undergoing turbocharger repairs the attending surveyor recommended that lubricating oil samples be taken from the main engine for analysis. It wasn’t done, and several days later during another loaded passage, the main bearings and then the crankshaft failed leading to towage, large general average costs and extensive disputes over seaworthiness.
Findings:
lubricating oil filter elements missing;
system “O” rings missing;
no record of analyses;
oil condition so bad, holes punched through filter elements with a screwdriver to allow oil flow;and/or
waste oil being recirculated back into the crankcase.
Actions to be taken:
The whole process of taking samples, landing the samples for analysis, obtaining the laboratory results and associated recommendations can be accomplished quickly. The process necessarily involves the vessel’s technical managers/owners as the feedback from the laboratory is initially to them – thence to the ship with associated instructions.
Therefore there is a due diligence aspect to the correct handling of the analysis process and this again can cause major legal disputes when not followed by the managers. Medium and high speed engines are particularly susceptible to depleted lubricating oil properties.
Bearing design takes into account at least the three components crucial to the system; the bearing shell itself, the other surface that it interacts with (co-operating surface), and the lubricant between the two.
Each of these components must work together to prevent the system from failing. During the design phase, engines generally have specific desired power output specifications and operating conditions and it is from these and other considerations that the systems’ preliminary designs are drawn.
Read the case study in full: Lubricating-Oil-Maintenance-is-Critical
