A member has reported an incident in which a crane load fell 1-2 metres as a result of a riding turn. During a project mobilisation in the hours of darkness, a small tool basket (<30kg) was being lifted from the quayside to the deck of the vessel. Despite the poor lighting conditions, the crane driver noticed a riding turn on the whipline winch. He informed all personnel in the vicinity to stand clear and having confirmed they had done so, he manoeuvred the jib and the basket fell about 1-2m. He then raised the load and slewed round to the stern of the vessel. The riding turn was remedied with the assistance of the bosun and the crane returned to normal service. There was no damage to equipment and no injuries.
This incident was not reported to any supervisory personnel until later in the shift when another unrelated incident occurred. This crane incident came to light in the subsequent discussions and further investigation of this incident took place. It was noted that the whipline had been greased recently and the viscosity of the grease was such that the wire became sticky when passing through the cheek plates on the jib. Further investigation revealed that the headache ball system had been changed from that used originally. A non-locking hook arrangement weighing 302kg was replaced with a locking one weighing 20kg. The combination of the light load, light headache ball arrangement and adhesive grease caused the riding turn on the winch drum.
The following conclusions were drawn:
- The action of the crane driver and bosun had successfully rectified the riding turn, but the riding turn was only a symptom of a deeper problem;
- The cause of the riding turn was not fully established at the time and could have easily occurred again, possibly with more serious consequences;
- The headache ball change-out was conducted without use of management of change procedures, and the reason for the change was not established or recorded;
- Because the incident was not reported when it occurred, there was no opportunity to:
- identify root causes;
- apply appropriate corrective actions;
- communicate the lessons learnt to personnel on the same vessel and throughout the fleet.
- A heavier temporary arrangement was installed later in the shift and a permanent arrangement was ordered for later installation;
- Personnel should be encouraged to report seemingly benign events to supervisory and management personnel who can then judge whether or not further action is required;
- Personnel should be encouraged to enquire further when the unexpected happens – simply asking the ‘why’ question could have revealed a number of relevant facts which can then be acted upon;
- Our member required personnel to manage change effectively, particularly when conducting work for which an existing plan is not proving effective or when making substantial changes to equipment and systems.
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