Snap-back Accident Causes Serious Injury

The UK’s Marine Accident Investigation Branch (MAIB) issued a safety bulletin following a mooring line failure on the LNG carrier Zarga, which injured a deck officer.

In early March 2015, a deck officer onboard the Zarga was struck in the head by a mooring line that parted during a docking at the South Hook LNG terminal, Milford Haven. He had to be airlifted to a hospital for emergency surgery.

Snapback danger was identified in the ships risk assessments procedures, but critical zones were not been marked on the tanker’s deck. The MAIB did a series of tests and trails to measure elongation and snapback characteristics:

• When connecting synthetic tails to UHMPE, HMPE and wire mooring lines, the energy introduced due to the elasticity of the tails can significantly increase the snap-back hazard.

• Elongation is proportional to the length of tail. Increasing the length of the tail will increase the amount of elongation and hence the amount of energy that can be stored in the line when under load.

• Ship owners/operators should ensure that the type of lines and tails used for mooring lines are suitable for the task and that the dangers of snap-back are fully considered.