Mars Report – Lessons learned
The Nautical Institute has issued Mars Report regarding an incident where unexpected lifeboat release injured crew member.
The Incident
During maintenance, the second engineer noted that the free-falllifeboat release system hydraulics appeared to be losing oil and hewanted to personally confirm that all was in order. In order to enter thecraft, the free-fall release safety pin had to be withdrawn.
Once insidethe lifeboat and after topping up the reservoir with oil, he decided topressurise the system and identify any obvious oil leaks. After pumpingthe handle three or four times he felt the lifeboat shudder and move.(Under normal circumstances, the lifeboats hook release devicewould require about 1012 cycles of the hydraulic pump to trip theon-load release.)
He saw that the lifeboat had begun to move down thelaunching rails; as there was no time to escape, he sat down in a seatand attempted to fit the seatbelt. The two simulation wires, in place toallow for launch training but so as to prevent an actual launch, failedunder the shock load and the lifeboat launched into the sea.
On the bridge, the OOW was alerted by crew who had witnessed thelaunch. He immediately activated the ships general alarm, slowed theship, and made an emergency announcement over the public addresssystem. Meanwhile, although injured, the second engineer was ableto start the lifeboat motor and manoeuvre close to the ship. He wasrecovered soon afterward and later diagnosed with a fractured kneecap.
During the investigation it was discovered that the oil level was notactually low; oil had remained in the ram and had not returned to thepump reservoir. Additionally, it was found that the reset alignmentarrows could indicate that the hook was in the correct reset position,even if it was actually only in a partially reset position.
This conditionwas not apparent because of a cover fitted over the release mechanismand the lack of an indicator for the release linkage to indicate if the ramhad fully retracted (or not). Thus, the on-load release was unintentionallytripped after only four operations of the hand pump, because it wasonly partially reset.
Yet, even when released, the lifeboat should not have ended up in thewater. Many other factors contributed to the final, rather wet, outcome,including the following:
- There was no equivalent, alternative arrangement to the safety pin toprevent inadvertent tripping of the free-fall lifeboats on-load releaseduring routine operations, such as inspections and maintenance.
- The simulation wires were longer than required and had not beeninstalled as per the manufacturers design guidance. Therefore, oncethe on-load release was tripped, the lifeboat travelled significantlyfurther than it was designed to during a simulated release, with aproportional increase in the shock load placed on the wires.
- The manufacturers calculations did not take into account the shockload imposed on the simulation wires or the lifeboat and launchingframe mounting points.
- The Recognized Organisations process for the approval of thesimulation wires for maintenance and testing had not taken intoaccount the shock loading that would be experienced during testing.
Source:Mars Reports/ The Nautical Institute
