A vessel experienced a midship hose handling crane failure. The incident occurred when she was at the discharge port and preparing the crane to lift the hose for cargo operations.
During lifting the crane from the jib rest position, the luffing hydraulic cylinder top end sheared off, fell down. The catwalk railings underneath the cylinder were damaged. At the same time, the Jib had fallen back to the rest position with a sudden impact.
The jib is operated by a hydraulically actuated cylinder. The root cause of this failure was seizure of the piston rod end pin and corrosion due to lack of lubrication. The restricted pin movement caused an additional bending stress on the rod end whenever the luffing cylinder piston rod was being operated over a period of time. This bending stress caused the luffing hydraulic cylinder rod to shear off.
The Ship’s crew was unable to dismantle the old cylinder assembly and the seized upper pin. Shore assistance was required to remove the seized pin. The crane was made operational and load tested after installing a completely new cylinder assembly and upper pin. To avoid similar failures, it is extremely important to lubricate/grease all the moving parts of the crane at regular intervals, in particular, luffing cylinder piston pins, jib pivots, sheaves, hook blocks and wires and make sure that all parts are being maintained well.
posted 30 Apr '18, 16:00