In its latest Safety Flashes for July, IMCA describes a failure of moonpool hangar doors onboard a ship, while she was underway. IMCA notes that hangar doors were not part of the recommended planned maintenance system (PMS), and it was not possible to inspect the suspension points holding the door leaf.
The incident
Whilst a vessel was working, there was a failure and collapse of the moonpool hangar doors. Deck crew were working in the area of the moonpool, when they heard a loud bang. When they turned around they could see that the hangar door had fallen down and folded in the guide rails. The door was 7.2 meters wide, 13 meters high and weighed approximately 200 kg. There were four crew members in the hangar at the time of the incident.
Probable causes
The suspension points for the hangar door leaf had failed. The causes were:
- Inadequate and weak design for holding hangar door leaf to head box;
- Increased wear and tear because there were no formal instructions or procedure for the operation of the hangar door;
- Possible additional wear and tear due to suction from the moonpool;
- Hangar doors were not part of the recommended planned maintenance system (PMS), and it was not possible to inspect the suspension points holding the door leaf.
Lessons learned
- Highlight the importance of knowing the operational limitations or requirements for any equipment;
- Ensure that personnel operating equipment (e.g. hangar doors) are properly familiarized with it;
- Consider further possible risk of potential dropped or falling objects, especially where inspection of condition is not possible.
What actions were taken?
Actions taken
- Implemented proper instructions for the operation of hangar doors and updated familiarization;
- 6mm stainless steel flat bar was installed inside an aluminium profile holding the folding door to header box in order to make the construction more rigid and solid;
- Installed safety lashings to prevent the folding door upper mount from falling to deck if overloaded.
