Fatality on board the off-shore supply ship Maersk Runner

Summary

On 28 July 1993, the off-shore supply ship Maersk Runner was employed running out anchors for the mobile drilling unit Atwood Falcon in the Walkley-l field, on the Australian North-West Shelf.

This operation involved the use of a 64 mm diameter working wire, or "chaser wire", which is used to haul the anchors out to the correct position and then to lower the anchors to the seabed.

As a dedicated chaser wire had not been provided, the ship had been using the starboard, 70 mm towing wire. When this towing wire parted, early that morning, a composite chaser wire, made up from a number of wire pendants shackled together, was used.

In the early part of the afternoon, one of the anchors failed to set in the seabed and had to be lifted and repositioned. As Maersk Runner started to lift this anchor, the composite chaser wire parted at a spelter socket, positioned just off the winch. The Mate was struck and thrown by flaying wire, suffering severe head and pelvic wounds, as a result of which he died.

Conclusions

1. The Mate died as a result of injuries received from being struck and thrown by the chain on the end of the port tugger wire and/or the 64 mm diameter chaser wire.
2. The cause of the Mate being struck by the chain/wire was the failure of the spelter socket at the inboard end of a 200m, 64 mm diameter wire pendant, shackled to the ship's working wire and being used as part of a "composite" chaser wire.
3. The spelter socket failed because of the effects of shock overload when the chaser was "homed" on the anchor.
4. The Mate's standing in an exposed position was brought about by the requirements of the particular operation.
5. The operation of using tugger wires on chaser wires, although not a common or usual practice, is necessary when using a composite wire with connecting shackles and sockets within its length.
6. There was no negligence on the part of the Mate, the Master or crew of Maersk Runner.
7. The long, straight stirrup "Crosby" design of spelter socket is not suitable for spooling on to a winch drum of a diameter the size of the normal working drum.
8. Chaser wires should be of one continuous length, to avoid shackles and spelter sockets being spooled on to the drum, and thus also avoid the need for the use of tugger wires.