What exactly happened? Operated by Shell International Trading and Shipping Company (STASCo), the ZARGA, a Q-Max LNG vessel, could only be moored in an exposed location at the South Hook Liquefied Natural Gas terminal in Milford Haven, UK. While repositioning the ship along the jetty during a ‘warping’ action using the spring-lines, one of the forward spring-lines failed. The rope, which was made of high-modulus polyethylene (HMPE), failed in-board close to the roller pedestal that leads the rope from the winch at a 90° angle to the roller fairlead. The energy stored in the rope’s PP/PET (polypropyleen/ Polyethyleentereftalaat) tail resulted in a high-speed retraction of the parted rope. Due to a complex snap-back trajectory, the rope hit the officer monitoring the operation on the back of the head, even though he was in a designated safe area.What caused the rope to fail?