Warning over 'normalised' towline failures after crew injured on tug Svitzer Avon

Two crew on board the UK-registered tug Svitzer Avon sustained minor injuries after a towline parted under load during a ship assist operation involving the car carrier Auto Eco at Royal Portbury Dock, Bristol, on 4 February 2025. 

Svitzer Avon and Svitzer Brunel had exited the lock shortly before 20.00 to meet the inbound vessel. With a pilot on board Auto Eco, both tugs were engaged for the approach and lock entry. A pre-manoeuvre arrangement placed Svitzer Avon's mate at the controls under the supervision of a relief master who, while type-qualified, had limited experience on that specific vessel. 

By 20.03, Svitzer Avon was secured astern of the carrier via a towline assembly led through the forward staple and held on the winch brake without engaging the render-recover system. Shortly after, the pilot instructed the tug Svitzer Brunel to standby on the port bow, followed shortly afterwards by the instruction ‘25% straight back’ to Svitzer Avon. During the vessel's turn to align with the lock, Svitzer Avon experienced a significant shear and heel following an overcorrection in handling. The towline failed under the resulting peak load. 

The recoiling rope struck the wheelhouse, shattering forward and stern glazing. Flying glass caused minor injuries to both the master and mate. The crew subsequently changed to Svitzer Brunel to complete the berthing safely before returning for medical attention. 

Findings and conclusions 

Investigators found that the relief master was not authorised to supervise the manoeuvre and that the company’s training regime lacked clarity and oversight. The tow rope had a previous failure history and parted again after 307 further tasks due to excessive dynamic loading, not material defect. The operator’s reliance on visual inspection and rotation of ropes fell short of best practice, with no residual strength testing conducted. Although glazing met required standards, risks associated with snapback remain significant. The MAIB investigated a similar accident involving Svitzer Mercurius in 2019.The chief inspector of marine accidents has expressed concern that towline failures may be becoming normalised, urging Svitzer Marine Limited to strengthen measures to prevent failures and mitigate crew injury risks, including revisiting earlier safety recommendations on wheelhouse protection. 

Svitzer has acknowledged the findings and taken steps to address them, including formalising trainer roles, introducing a structured type-rating framework, reviewing rope failure incidents, and aligning rope selection with operational risk. However, the MAIB stressed that further action is required, particularly on towline management and snapback mitigation.