A new study evaluating methods of establishing tow lines between an escort tug and a tanker in distress is a prime example of why the Council’s studies are vital.
The Council often hires experts to review equipment technology used in the Prince William Sound oil transportation industry. Sometimes these studies fill a hole or gap where independent research is lacking.
“Very little has been previously written on this topic,” said Alan Sorum, who managed this project and other similar technology reviews for the Council. “In a literature review it conducted, the Council’s contractor, Glosten, found that there is a general lack of published material on this subject and in particular, little guidance on best use practices or what is the most appropriate device to use for a given situation.”
The study looked at a specific piece of equipment called a “messenger line.” Passing a messenger line is the first step in setting up a tow line between a tug and a tanker in distress. The lighter weight messenger line helps responders connect the heavy tow lines.
Retrieving a messenger line can be difficult and dangerous in the rough weather often encountered in Prince William Sound. Depending on the vessel and the technology on board, they may be passed by hand, heaved or thrown aboard, projected by mechanical means, or picked out of the water.
Tough equipment required for Alaska’s harsh climate
Alaska has a state law that requires tankers to carry specially designed towing equipment when traveling through Prince William Sound. This equipment includes a towing wire, floating line and buoy, and a heavy-duty shackle.
These components are all specifically sized to match the weight of the vessel and be able to handle the high winds and seas often encountered in Prince William Sound.
Having this specialized equipment on hand allows rescue tugs to quickly and safely help move a stricken tanker to a safer location.
Conducting the study
Researchers reviewed what devices are commercially available for deploying messenger lines. Next, they developed criteria to evaluate the equipment according to: effectiveness, feasibility, transferability, compatibility, age and condition, availability, environmental impacts, and cost.
These eight criteria were based on another Alaska law, which requires industry to use “best available technology.” This requirement is intended to ensure that equipment meets and is maintained to a high standard.
The equipment options were each assessed and scored.
How will the Council use this information on tow lines?
The Council’s influence depends on quality, accurate research. The Council uses reports like this to help make sure advice given to industry and government officials is well-informed and supported by the best science available. The findings of this latest research effort are being shared with equipment manufacturers, the oil transportation and shipping industries, and regulators.
Read more about the researcher’s recommendations:
Tanker Towline Deployment BAT Review (10.3 MB)
Report on towline trials conducted in summer 2021: