MAIB report into immobilisation and flooding of dredger Shearwater following repeated collisions published

At about 2000 on 9 April 2020, the UK registered dredger Shearwater was immobilised after its propeller shafts were fouled by a towline being used to tow the barge Agem One. The dredger and barge collided with each other repeatedly resulting in Shearwater being holed and flooded, before the towline parted and Agem One drifted away. There was no pollution or injury.

Shearwater had been towing Agem One in an alongside configuration on a coastal passage when a significant swell was encountered. This made the alongside tow untenable, causing Shearwater’s crew to switch to an astern tow. Within minutes of
switching, the 80m towline failed. Shortly after reconnecting the towline, it failed again, and the decision was made to abort the planned passage and seek shelter at Kinlochbervie.

During the passage to Kinlochbervie the crew had reverted to an alongside tow and, in preparation for entering the narrow channel into the harbour, the towing arrangement was again reconfigured to tow the barge astern. It was during this evolution that the towline became fouled around Shearwater’s propeller shafts and the immobilised dredger was damaged. The situation was eventually brought under control after the intervention of a lifeboat, the emergency towing vessel, Ievoli Black, and the workboat Forth Drummer.

The accident happened because there was insufficient planning, risk assessments, or safe systems of work for the towing operation being conducted. Shearwater was not suitable for use as a coastal towing vessel especially through hazardous areas such as the Pentland Firth, and the crew did not have the necessary competence to undertake the operation.

Shearwater was too large for certification as a small commercial vessel but under the tonnage requiring a safe manning certificate or safety management system. This investigation has identified that the flag state’s arrangements for certifying Shearwater using exemptions from the Load Line Regulations did not provide sufficient guidance to assure safe operation of the vessel.

Since the accident, Shearwater’s owner has purchased a small tug for use when repositioning barges. Nevertheless, recommendations have been made to Shearwater’s owner to assess all on board hazards and provide safe systems of work to mitigate the foreseeable risks, and to ensure the vessel is safely manned. This report also makes a recommendation to the Maritime and Coastguard Agency to ensure that certification of vessels such as Shearwater includes the application of all appropriate regulatory conditions relevant to the vessel’s intended function and area of operations.

Key Safety Issues
– Shearwater was not a suitable vessel to conduct a lengthy coastal tow, and there was insufficient planning or safety procedures for the voyage
– Shearwater’s crew did not have the necessary competence for the towing voyage, and there was no tow master
– Safety certification by the flag state did not provide sufficient assurance for safe operation of the vessel

Recommendations
Recommendations (2021/124 and 2021/125) have been made to Shearwater’s owner to assess all onboard hazards and provide safe systems of work to mitigate the foreseeable risks, and to ensure the vessel is safely manned.

This report also makes a recommendation (2021/123) to the Maritime and Coastguard Agency to ensure that certification of vessels such as Shearwater includes the application of all appropriate regulatory conditions relevant to the vessel’s intended function and area of operations.

Download the full report: Shearwater MAIB report

Download the annexes to the report: Shearwater MAIB annexes

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