A UK dredger was holed by a barge it was towing when the tow line became fouled in the propeller shafts, an accident report has revealed.
The incident occurred on 9 April 2020 near Kinlochbervie, Scotland, when the 37-loa dredger Shearwater (built 1968) was immobilised when the cable to the 21-loa barge Agem One (built 1992) became entangled.
The Shearwater was damaged and breached, resulting in flooding, after repeated collisions with the Agem One, which was no longer under control, the Marine Accident Investigation Branch (MAIB) said.
The situation was eventually stabilised after the intervention of a lifeboat, a workboat and an emergency towing vessel.
Both the dredger and the barge are operated by UK company Northern Dredging, which could not be immediately reached for comment.
MAIB found the dredger was not a suitable vessel to conduct a lengthy coastal tow, and there was insufficient planning or safety procedures for the voyage.
Crew experience insufficient
"Shearwater’s crew did not have the necessary competence for the towing voyage, and there was no tow master," the report added.
MAIB also said that safety certification by the UK flag state did not provide sufficient assurance for the safe operation of the vessel.
The report made recommendations to Northern Dredging to assess all hazards on board and provide safe systems of work.
Since the accident, the Shearwater’s owner has purchased a small tug for use when repositioning barges.
The Maritime and Coastguard Agency was also asked by MAIB to ensure that certification of vessels such as Shearwater is appropriate.
There was no pollution or injury in the accident.
Heavy seas changed plan
The Shearwater had been towing the Agem One in an alongside configuration on a coastal passage when a significant swell was encountered. This made the alongside tow untenable, causing the Shearwater’s crew to switch to an astern tow.
Within minutes of switching, the 80-metre tow line failed.
Shortly after reconnecting the line, it failed again, and the decision was made to abort the planned passage and seek shelter at Kinlochbervie.
During the passage there, 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 that the tow line became fouled.
