High Copper concentration in Stern Tube LO

Good day everybody.
Does anybody have past experience with increased Copper concentration (60ppm-80ppm) in Stern Tube LO? What actions were taken in your case?


Hello Kostas!
Assuming that the stern tube bearing in question is tin-based, then the high copper content would normally not indicate abnormal wear in the stern tube bearing.
The high copper content could be possibly related to wear and tear of the stern tube cooler or the stern tube circulating pumps.
A proposed action plan, in the case that the vessel will not be drydocked soon, would be: a)to renew partially the stern tube oil b)land again lube oil samples (allow some time for thorough flushing) c) inspect the stern tube circulating pump filters and d) observe the trend of copper content.