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Use of Back-Up Mode Implicated in Aurora Explorer Allision

Aurora Explorer courtesy of Arctic Explorer AS
Aurora Explorer courtesy of Arctic Explorer AS

By The Maritime Executive 07-04-2019 05:45:18

Norway's Accident Investigation Board has released its report on the 2018 Aurora Explorer allision, implicating the use of back-up mode operation in the incident.

On July 15, 2018 Aurora Explorer collided with the quay while docking at Barentsburg, Svalbard. Many of the 125 people on board, mainly French pensioners, were standing on the open deck during arrival. Many of them fell during the collision with the quay, and 37 passengers and one crew member suffered varying degrees of injury. The vessel suffered minor damage above the waterline, with no water ingress.

The investigation revealed that the vessel was operated in back-up mode in order to achieve cruising speed under way. This allowed the possibility of an oversight to arise where a master could forget to re-set the system to combinator mode before docking.

On arrival at Barentsburg, the vessel was possibly still being operated with the port drive line in back-up mode, so that the propeller on the port side could still have been carrying forward pitch. The vessel’s speed towards the quay increased when the master, following normal practice, pulled the port maneuver handle to astern, in order to swing the stern in. When the maneuver handle was pulled to astern, the rpm on the port engine increased, if the system on this side remained in back-up.

Vibration Problem

In the winter 2018, a service engineer overhauled the engine gearbox, but the supplier of the maneuvering system was not contacted to ensure optimal adjustment of pitch and loading. The port drivelines propeller pitch was not correctly adjusted after this gearbox overhaul. This caused severe stress at certain rpm settings and vibrations in the vessel.

Challenges caused by vibrations in the vessel on cruising speed continued when the vessel had started to operate around Svalbard. Those responsible for the vessel did try to readjust the
system. When this was not successful, it was decided to operate Aurora Explorer in combinator mode during docking and in back-up mode to reach cruising speed between destinations in order to limit unwanted vibrations.

The Maneuver

Leading up to the allision, the vessel reduced speed to eight to nine knots approximately 600-700 meters from the quay and then reduced speed gradually as she maneuvered towards the quay.

In Barentsburg, there were two places on the main quay which the vessel could use. The place at the southern end of the quay was already occupied by another passenger vessel. Aurora Explorer approached from the north and started a standard U-turn to dock against the quay starboard side to. This was the preferred side, because of the vessel’s gangway arrangements. The master broke off the U-turn earlier than usual, in order to avoid a shallower area and keep a safe distance from a vessel lying at the quay astern. Aurora Explorer then came relatively parallel in alongside the pier before the planned mooring.

According to the master, speed was reduced to around three knots. Around 10-20 meters from the quay, the port engine suddenly increased power. The vessel swung uncontrollably to starboard, which led to the starboard foredeck colliding with the fenders on the concrete quay.

The submerged part of the starboard hull passed in under the quay. The collision led to passengers and crew being thrown forwards on the open deck and in the saloon below. The vessel sprang back from the fenders after impact, causing people to be thrown about again. The master disengaged both engines immediately after the collision. When he then re-engaged them in combinator mode, the engine, steering and maneuver handles functioned normally. Aurora Explorer was then moored with her starboard side against the quay.

Risk Assessment

The investigation showed that the shipping company had not assessed the risks to passenger safety that might result from changes in operational mode. The shipping company was unable to produce any assessment of the back-up operational mode that was chosen, with its attendant risk of nonconformity.