If a line or bollard fails under stress, a cascading effect can occur as each of the remaining lines or bollards become overloaded. This happened with passenger vessel Seabourn Encore and highlights the importance of monitoring the safe working loads of lines and bollards.

The accident occurred on 12 February 2017 in PrimePort Timaru, New Zealand. The official accident report by the Transport Accident Investigation Commission (TAIC) New Zealand was released in February 2019 and the incident was discussed in Mars Report number 323 (September 2019). The Mars Report gives a transcript of what happened:

The Seabourn Encore was docked in good weather and light winds. Six headlines, six stern lines and four spring lines were made fast as shown in the diagram below.

The Seabourn Encore was secured with a total of sixteen lines on fifteen bollards.

About seven hours later, the wind changed direction and increased considerably to about 25 knots, pushing the vessel away from the wharf. Almost immediately after this first increase in wind, a squall blew up with winds reaching 45 knots.

The master ordered engines and bow thrusters to help hold the vessel, but seconds later one of the shore bollards holding a forward spring failed. Then an aft bollard and another spring bollard failed in quick succession. Before the vessel’s engines and thrusters could be used, three stern lines failed due to over-stress and the vessel’s stern came away from the quayside.

As the stern swung out, it contacted another ship (cement carrier Milburn Carrier II) and berth, as shown in the image below. Sometime later, when the winds had subsided somewhat, the Seabourn Encore was re-secured alongside the berth with tug assistance.

Damages

Although there were no injuries, there was considerable damage. The Seabourn Encore sustained minor indentation damage to the port quarter above the waterline. The Milburn Carrier II sustained damage to the hull, causing a breach of watertight integrity on the starboard side midships in the vicinity of the waterline. PrimePort Timaru sustained damage to wharfs one and two.

Investigation Findings

The investigation found that the port company had virtually no knowledge of the actual safe working loads (SWL) of the various mooring bollards on the wharf. It was also discovered that the method with which the bollards had been fastened to the wharf and/or the strength of the underlying wharf structure meant they were unable to withstand the forces imparted on them by the vessel’s mooring lines.

Accident Prevention

Knowing the safe working loads of the various mooring bollards in a port is critical to safe ship operations. While this is primarily a port function, it is always a good idea to take a walk on the dock and have a look at the bollards – do they look good? Is the SWL of each bollard indicated?

In the event a line or bollard fails, take immediate and positive action to control the ship’s potential movement.

Picture (top): The Seabourn Encore (by Eduard Marmet).