Towline recoil damages tugboat wheelhouse, injures two seafarers

Following the accident on Svitzer Avon, the 28.2-m tug continued helping another tugboat, Svitzer Brunel, to assist Auto Eco through the lock and berth in the dock at Royal Portbury Dock.

Svitzer Avon returned alongside and was met by the port’s medical team. The master and mate were then transferred to hospital, treated for their minor injuries, and later discharged.

The MAIB discovered that the tow rope failure was caused by “excessive towline assembly loading experienced during an overcorrection in a ship-handling manoeuvre,” the investigation branch said in its report.

It found that the tow rope had previously parted in July 2024 after 800 tasks and had been changed end-to-end to keep it operating for multiple more tows. The tow rope subsequently parted on its 307th task.

“The towage company relied on visual inspection and tow rope rotation for towline risk management,” the MAIB said.

“The company did not follow best practice nor conduct residual strength testing on parted ropes or as part of its towline risk management system.”

Another finding by the MAIB was that the manoeuvre that resulted in the towline failure was undertaken by the tug’s mate supervised by the relief master, who was type-qualified for the tug but had little experience on Svitzer Avon and was not authorised to supervise the mate during the move.

“The towage company’s training regime was not clearly defined or closely monitored,” said the MAIB.

Following the February 2025 accident and MAIB’s investigation, tug manager Svitzer Marine Limited has formalised the designations of training masters and introduced a trainers pathway and training groups to standardise training practices across UK regions.

The Danish shipowner has introduced a type-rating framework of formalised training requirements for different vessel classes; reviewed rope parting incidents and assessed impacts across the business; ensured rope selection and usage align with operational risk.

MAIB’s chief inspector of marine accidents has written to the managing director of Svitzer Marine expressing concern that “towline failure has become normalised and that, consequently, the associated risks are not being mitigated.”

Following the MAIB investigation into a similar accident involving Svitzer Mercurius in 2019 it provided recommendation 2022/138 to Svitzer Marine to undertake a fleetwide assessment to determine the level of risk associated with towline failure and snapback.

It also recommended a risk assessment of the potential for impact by a line recoiling into wheelhouse windows, and, where appropriate, employ appropriate laminated glass or other defences to mitigate against the risk of flying glass injuring its tug crews.

Subsequent to its Svitzer Avon investigation, the MAIB chief inspector has urged Svitzer Marine to reconsider its actions in response to MAIB Recommendation 2022/138 and “implement measures to both minimise towline failures and mitigate the risk of crew injury should a towline part,” said the MAIB.