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Near miss: grinder disc rotation set up in the wrong direction

What happened

In preparation for a forthcoming dive a GR29 underwater grinder was requested to be set up by the topside technician to be used for left-handed cutting to assist in gaining access to the cut.

The diver, on receiving the left handed grinder, carried out pre-operational equipment checks, where it was identified that the disc rotation was found to be in the wrong direction. The operations were stopped.

What went wrong

On investigation, it was identified that the GR29 grinder set up to be operated left-handed, was rotating in the opposite direction, leading to a risk in the cutting disc lock nut coming off. It was identified that the reversing spool had been re-orientated after discussions with onshore personnel. 

The modified GR29 grinder was recovered to the surface and quarantined.

Operations continued with the confirmation that the original un-modified GR29 grinder was operational and the standard process of changing the handle and re-orientating the guard was continued.


The company standard/recommended process for a change in orientation of the GR29 grinder is for the GR29 grinder handle to be re-positioned 180 degrees right/left and the GR29 grinder guard repositioned and the direction of rotation to remain unchanged.

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