A Canadian safety board explains how operators can identify tug girding during tows and how to prevent capsizing
Transportation Safety Board of Canada (TSB)’s investigation into the capsizing of tug George H Ledcor on the Fraser River, British Columbia on 13 August 2018, uncovered the extent to which tug owners and operators are unaware of the dangers of girding (or girting) and how to avoid a capsize.
George H Ledcor girded and overturned while towing the loaded gravel barge Evco 55,
assisted by tug Westview Chinook, to an unloading facility in the north arm of the Fraser River.
Investigators found the girding and capsizing happened quickly when George H Ledcor was overtaken by the barge and despite attempts to change the direction of the barge.
“As the barge began to overtake George H Ledcor, the towline exerted a broadside force on the tug, placing it in a girded position” TSB says in a report published 2 October. “The master applied full starboard rudder and full throttle. However, the various forces acting on the tug’s stability combined to increase the tug’s heel.
“As the tug’s deck edge and bulwarks submerged, the tug heeled further to starboard. Attempts to abort the tow were unsuccessful and the tug rapidly capsized.” A crew of four were able to escape and were rescued soon afterwards.
The investigation highlighted several risk factors, including tug masters not providing initial and recurrent training and towing companies relying primarily on tug masters to manage girding hazards through ship-handling skills and informal practices.
This was not a one-off occurrence. Between 2005 and 2018, TSB received reports of 26 girding situations resulting in 21 capsizings. As a result, TSB issued advice to towage companies on how to identify dangerous situations and how to rectify them.
“Girding happens rapidly and is a high-impact event,” TSB says in an information video. “The consequences are serious and can be fatal.” Girding happens when the tug is turned broadside by a towline force and is unable to manoeuvre out of this position.
“When we investigate these incidents, we discovered that few operators are instructed on how to recognise the factors that cause a girding situation and how to avoid and deal with it,” TSB says.
Factors that can lead to a girding situation include the suitability of the tug for the tow – including its power, size, manoeuvrability and visibility – the towline length and towing point, which affect tug stability.
Tow characteristics – size, weight, momentum and pivot point of the tow – affect the tug’s ability to control. Environmental conditions – wind, tide, current and water depth – and watertight integrity will affect whether a tug can recover from a girding situation.
“When one or more of these are not taken into consideration, girding and capsize can occur,” says TSB. “Girding can be prevented by understanding the dynamics and risk factors. Depending on the severity of the situation, tugs can recover from a girding situation.”
This can be achieved by adjusting towline length and repositioning the tug in front of the tow; using the assisting tug to reposition the tow; and flopping the towing tug alongside the barge until it can be safely repositioned.
TSB recommends abort mechanisms on tugs should be “highly visible, similar in style and in familiar locations so in an emergency they can be quickly identified and accessed.” TSB also said it was important for owners and operators to “provide guidance, information and training to prevent girding”.
Factors that can lead to a girding situation
Video from TSB’s accident report and future recommendations to tug operators: