Incident Information on Fatal Accident with Lifting Appliance

This incident information refers to a fatal accident involving a lifting appliance. A provision crane loaded pallets onboard a vessel using a pallet fork. After landing the pallet on the vessel’s deck, the pallet fork was cleared and the crane operator moved the crane outward to pick up new load. During this operation, the crane wire broke and the pallet fork and the hook fell down and hit one of the crewmembers on the vessel. Despite the effort of the vessel’s own crew, dedicated first aid personnel and a doctor, the injured person died shortly after the accident.

2013.08.02 - Incident Information on Fatal Accident with Lifting Appliance Figure 1

Two important reasons that allowed the failure to occur are:

  • Malfunction/missing upper limit switch. If the upper limit switch had been operational, it would have stopped the movement before the hook was able to hit into the crane beam. The wire end at the hook side was terminated by means of three incorrectly applied U-bolt clamps instead of a ferrule lock devise as prescribed in Maker’s manual (see figures below).
  • Tests has shown that this lead to a considerable reduction of the breaking strength of the wire resulting in a breaking  strength below the loading in the wire when the hook blocks hits into the crane beam with full hoisting speed.

2013.08.02 - Incident Information on Fatal Accident with Lifting Appliance Figure 2

The above figure shows the incorrect methods of attaching clamps to wire rope.

2013.08.02 - Incident Information on Fatal Accident with Lifting Appliance Figure 3

The above figure shows the example of a ferrule lock suggested in makers manual for this incident.

Lessons to be learned from such incidents are highlighted below:

  • Limit switches are important safety related measures on a crane. It is recommended that the limit switches are tested regularly and confirmed to work as intended. Note that for electrically driven winches without any torque limiting device, the hook upper limit switch is particularly important. The hook upper limit switch may for instance be tested by hoisting the hook slowly upwards until automatic stop imposed by the limit switch. Further, visually verify that the hook will hit the limit switch independent of motions due to wind and waves or operational effects.
  • Assure that wire end terminations are correctly performed. Note that DNV rules do not allow the use of U-clamps, but properly designed clamps with two gripping areas are accepted (see figure below).
  • Inspect the appliance before use. Preferably apply a “Before use inspection checklist” accepted by the crane maker and the crane certifying authority.
  • Respect for established procedures with the aim to avoid persons under or nearby hanging loads. Make sure that all crew members are properly informed of the hazards involved in lifting operations and the precautions they are expected to take.

2013.08.02 - Incident Information on Fatal Accident with Lifting Appliance Figure 4

Source: DNV

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