Marine Engineering Study Materials

Chief Engineer is requested to conduct cross head bearing survey of the engine of another vessel following an unscheduled repair due to bearing failure.

Information Required for Cross Head Bearing Survey

• Obtain from Class the identification of which cylinder crosshead bearing is to be inspected.
• Obtain from the vessel the records of any previous inspections/maintenance carried out on any engine bearings, especially the crosshead bearing under survey inspection.
• Also obtain the latest indicator cards and log readings taken from the engine to inspect for excess cylinder pressures, and the latest lube oil analysis to inspect for lube oil condition and impurities.
• Check that there are no outstanding Conditions of Class on the engine that could affect the crosshead bearing.

Procedure for Cross Head Bearing Survey

The old bearing would be inspected to attempt to identify the cause of failure, and to ensure that the replaced bearing will not suffer a similar fate in the short to medium term. The following areas would be inspected (assuming only the bearing is to be replaced):

• Surface condition of the bearings to ensure no corrosion present
• Strong attachment of the white metal to the bearing lining
• Clear and adequate oil reservoirs on the lower half
• No corrosion present on the bolts
• All fastening devices to be renewed
• Visual inspection of the crosshead guides for security is bolted, and /or cracks in the frames especially when welded
• Visual examination of the crosshead guide bearings where possible
• The pin would be inspected thoroughly for cracks by NDT (Non Destructive Testing) methods, especially in way of any radii.
• The pin would also be examined for scoring and overheating caused by the bearing failure. None should be present.
• Visual examination of the oil input pipe for defects and ensure free movement/operation

Inspection After Assembly

• Once the bearing has been assembled, all crosshead clearances would be taken, checked with maker’s tolerances, and recorded.
• The lube oil pump would be started to ensure a flow of oil from the bearing, and the engine turned on the turning gear to ensure that no restriction to movement is present.
• Class would be informed by written statement of all readings taken, and that a visual inspection was acceptable.