Rocking Test of Deck Crane

As I mentioned in my writings, nowadays, I am working in the office maintaining hydraulic equipment through a Computerized Maintenance Management System – CMMS.

The hydraulic equipment’s I maintained are from deck machinery: deck crane, windlass, tugger, anchor handling winches shark jaw and towing pin.

I want to discuss about rocking test of deck cranes. Considering my experience on-site gain so far I recommend the test to be done during dry dock repairs or plan maintenance period PMP.

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Rocking test means checking the condition of the slew bearing of the deck crane. It’s an important items of the crane and if not grease properly the slewing bearing may become worn with bad results.

Before climbing on the crane , first thing I do is to check the condition of the crane from outside. When the outside surface below the slewing ring is clean then the ring is at risk. The outside area of a proper maintained ring has to be with visible trace of grease.

I remember when a slewing bearing was laying on the floor in the workshop with deformation and a crack.

I’ve done this test few times. I measured for wear of the slewing bearing and took sample of grease from the inner seal. If the wear measurements showed wear than grease sample should be taken and analysed it. All the time I found it in good condition.

I was inspected the old grease for the presence of metal fragments. The presence of significant amounts of metal fragments in the grease is a sign that bearing is in a dangerously worn condition.

As per ABS Class rocking test of the deck crane is a requirement prior to load test with the surveyor witness of the test.

So nowadays when maintaining of deck crane I’m careful the slewing bearing to be frequently measured and properly greased.