Encounters At Sea
Certificate of Merit
AE CRANKSHAFT FAILURE
21st Dec 2006
The Crankshaft of the Auxiliary engine is supported by bearings in 2-halves in a bearing housing. These bearing housings are also in two halves and held together by two fitted bolts. There is no way to check if these fitted bolts go slack.
There in a long banjo bolt between the fuels P/Ps of units, that is used as a lube oil pipe for lubricating the bearings of the camshaft. These banjo bolts also hold the camshaft bearing housings in place and do not let the housing turn.
In one of the ships that I served, one of the bolts got slackened and came out from the threads of the bearing housing. This made the bearing turn in place and stopped the lubrication to that particular camshaft bearing.
The bearing shells first broke and came out of the housing. This increased the clearance at that bearing housing. Since the cam shaft goes through a lot of shearing force due to various cams at various positions, the camshaft sheared off from the point of the bearing failure.