Norway's Petroleum Safety Authority, PSA, says an improperly adjusted winch brake, which it refers to as 'vulnerable', led to the unintentionally launch of a lifeboat from the mobile unit Mærsk Giant at about 05.10 on Wednesday 14 January 2015.
This incident occurred during testing of the lifeboat systems.
During testing, one of the lifeboats unintentionally descended to the sea. Efforts were made to activate the manual brake on the lifeboat winch, but it was not working. The lifeboat entered the water and drifted beneath the unit. The steel wires holding it were eventually torn off.
After the incident, the lifeboat drifted away from Mærsk Giant, accompanied by a standby vessel. The lifeboat eventually reached land at Obrestad south of Stavanger.
Nobody was in the lifeboat when the incident occurred, and no personnel were injured.
The PSA conducted an investigation which established that the direct cause of the incident was a reduction in the braking effect of the brake on the lifeboat winch owing to faulty adjustment. If the manual brake failed during maintenance with people in the lifeboat, or during an actual evacuation, serious personal injury or deaths could have resulted.
Should the lifeboat have descended during an actual evacuation, a partially filled lifeboat could have reached the sea without a lifeboat captain on board. The PSA also considers it likely that people would have been at risk of falling from the lifeboat or the muster area should a descent have started. The potential consequence could be fatalities.
Five nonconformities were identified by this investigation. These related to
- maintenance routines for the lifeboat davit system
- procedures relating to lifeboats and evacuation
- periodic programme for competent control and ensuring the expertise of personnel carrying out maintenance work
- qualification and follow-up of contractors.
Mærsk Giant is operated by Maersk Drilling Norge.