Lift bags broke free

A member has reported an incident in which lift bags broke free. Two ten-ton airbags had been deflated at the seabed in preparation for being lifted onboard the vessel. During recovery, the airbags broke free while taken through the splashzone. The vessel crew tried to keep visual contact with the air bags when on surface and move the vessel away from them but the air bags disappeared under the vessel and were assumed to have sunk to seabed. Two days later, during transit, the vessel crew saw that a thruster was experiencing increased power consumption and reduced revolutions. An ROV confirmed that one of the lost lift bags was caught in the thruster. The vessel went to port for further investigation and, as a result of an oil leakage in the thruster, had to be docked for repair.

Investigation revealed that the points used for lifting the bags were not appropriate certified lifting points but only user handling points. Subsequent tests demonstrated that these user handling points were insufficiently strong to carry the weight of the lift bag.

The company has made the following suggestions:

• Only use appropriate lifting points, do not use unidentified lifting points.
• Lifting points on lift bags should be clearly marked. Suppliers should be made aware of this requirement.
• Remove or stitch together the man-handling strops, to prevent the possibility of mistakenly using these for lifting the bag during installation and recovery.