What is the Rocking Test?

It is a test which is carried out to find, wear down of the
sleeve bearing of the deck crane on ships.

this measures the play (or relative movement) between the inner 
 and outer bearing race, to give an indication of the wear taking place.

(Wear down of the sleeve bearing can be found by analysing the grease sample.
The metal content  of the sample may give indication of wear down.)

The Rocking Test need to be carried out according to manufacturer 
recommendation

Measurements are typically taken in four positions on 
the slew bearing, with the jib pointing:

• forward to the ship
• starboard
• aft 
• port side.

Neither a load nor any cargo handling equipment should be attached to the hook.
It is important for the same positions to be marked as a datum reference..