Review of vessel traffic service technology

Photo of the Valdez Duck Flats.

The Council is beginning a project to review what constitutes best available technology in the field of vessel traffic control, conduct a survey of stakeholders of the Prince William Sound’s Vessel Traffic Service, and develop recommendations for potential improvements to the service.

The Vessel Traffic Service in Prince William Sound is one of 12 facilities operated by the U.S. Coast Guard around the country. Personnel at these facilities use surveillance and communications systems to reduce vessel collisions, allisions, and groundings. 

The Council is now accepting proposals to complete this project.

Read moreReview of vessel traffic service technology

New study analyzes weather at Hinchinbrook Entrance

A recent Council-sponsored report found that wind and waves at Hinchinbrook Entrance may be under reported as observed by the Seal Rocks weather buoy.

Researchers from Tetra Tech analyzed wind and wave data to better define weather conditions at the Entrance, as well as how these conditions might affect rescue operations by the escort tugs. To do this, researchers looked at the frequency and duration of weather events when the Entrance was closed to laden tankers.

Average closure conditions

A "wind rose" graphic that shows the speed and direction of wind as recorded at Seal Rocks.
This “wind rose” graphic shows the speed and direction of wind as recorded at Seal Rocks.

Wave height alone was found to be the cause of most of the closures, occurring 10 to 26 times a year on average. Average wave height during closures was over 17 feet and the highest recorded wave was over 26 feet. Wind speed closes the Entrance one to three times annually, as do closures for both wind and waves. Winds average just over 54 miles per hour during closure and the highest recorded wind speed was over 61 miles per hour.

Closures for winds typically last less than two hours, while waves close the Entrance for an average of just over six hours.

Seal Rocks buoy’s data may not be precise

Read moreNew study analyzes weather at Hinchinbrook Entrance

Out-of-service buoy and winter storms raise concerns

An out-of-service buoy and a series of recent storms have combined to raise concern at the Council about tanker transit procedures during period with the high wind speeds and wave heights in which tankers are allowed to travel through Prince William Sound.

Seal Rocks buoy out of service


From May until December of 2018, a critical buoy located near Hinchinbrook Entrance was out-of-service. This buoy, referred to as “Seal Rocks buoy,” collects wind speed and wave height data. That information is used by the U.S. Coast Guard to make decisions as to whether Hinchinbrook Entrance is open or closed to outbound laden oil tanker traffic. When this buoy is inoperable, the U.S. Coast Guard uses data from two nearby buoys, Cape Cleare and Cape Suckling, along with reports from Edison Chouest Offshore, or ECO, tug crews that are sent out to observe wind and waves to make Hinchinbrook Entrance open and closure decisions.

In November and December, several winter storms came through Prince William Sound that raised concern about these alternate methods for reporting weather conditions at the Entrance.

Read moreOut-of-service buoy and winter storms raise concerns

Oil spill prevention and response services transition to new contractor

Link to more photos of new equipment
More photos of new equipment.

Prince William Sound was a hive of activity this summer. On July 1, Alyeska’s marine services contractor transitioned from Crowley Maritime Corporation to Edison Chouest Offshore.

This transition means all of the escort tugs and much of the spill prevention and response equipment in Prince William Sound are brand new, or new to the Sound.

Demonstrations of the new equipment

The Alaska Department of Environmental Conservation required that each vessel and crew member demonstrate their capabilities before beginning service. Each tug, as well as each tug’s captain, had to perform a set of maneuvers which differed according to the vessel and its purpose.

Read moreOil spill prevention and response services transition to new contractor