Vessel Type: Bulk carrier

Incident description

A bulk carrier was discharging cargo alongside a mineral terminal. In order to re-position the vessel, the terminal requested the vessel's master to shift ship approximately 100 metres astern. At the required time, the crew were ordered to their mooring stations, and the main engine was placed on stand-by, ready for use. The plan was to move the vessel astern using only the mooring lines, which were to be transferred from bollard to bollard by the shore linesmen, with an ebb tide running from ahead. During the shifting operation, the master became concerned that the vessel was developing excessive sternway and ordered the forward and aft mooring parties to check the movement using the forward headlines and the aft back spring rope. On the poop deck, an A.B. tightened up the back spring winch brake and as the strain came on the rope, it parted without warning.  One end of the rope snapped back  violently and struck  the second officer. The injured seaman suffered broken ribs and serious internal injuries.

Analysis

This accident was the result of a loss of control during the shifting manoeuvre. Proper consideration was not given to the effect of a strong ebb tide on the vessel. Additionally, the main engine should have been used before control of the vessel was lost.

A synthetic fibre rope will stretch under tension, and if it parts when under load, the sudden release of stored energy will cause it to snap-back with great velocity, risking death or injury to anyone who gets in its way. It was determined that the rope parted due to local abrasion damage at the point of failure combined with the AB over-tightening the winch brake, preventing the brake from rendering below the breaking load of the rope

Lessons Learnt

• All mooring operations should be subject to a proper risk assessment and planned  to ensure that all involved crew are aware of how the operation is to be conducted, the potential hazards, and all required safety precautions
• Mooring machinery and ropes should be maintained and frequently checked in accordance with the manufacturer's instructions
• Over-tightening winch brakes may lead to the mooring rope breaking load being exceeded
• Be aware that the whole mooring deck is a potential snap-back zone during operations and always keep clear of mooring ropes when under tension