Researchers say ice drifting into tanker lanes will be smaller but more numerous in future

By Alan Sorum
Council Project Manager

Columbia Glacier Retreat, 1980-2015
Click map for larger image.

Columbia Glacier, located in the Chugach Mountains of Alaska, is losing mass faster than almost any other glacier in the state. Columbia is a tidewater glacier, a type of valley glacier that flows into the ocean.

In 1996, the council began a project to monitor and analyze the calving and drift of ice from the glacier, through Columbia Bay, and into Prince William Sound. The ice sometimes drifts into the established tanker shipping lanes. Loaded tankers leave their designated lanes to avoid this ice.

In 2012, the council began to update information developed in the original 1996 project to determine the future risk of Columbia Glacier icebergs to the tanker traffic. Funded by the council, researchers W. Tad Pfeffer and Shad O’Neel studied several aspects of ice loss at Columbia Glacier.

The study found that icebergs discharged by the glacier during the retreat have largely been contained within the moraine shoal, located at the position of the terminus prior to the glacier’s retreat. The fraction of icebergs that cross the moraine and enter Prince William Sound proper still pose a potential hazard to ship traffic in the Sound.

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New regulations mean cleaner air in Prince William Sound

By Austin Love
Council Project Manager

Crude oil tankers in Prince William Sound are using cleaner fuel than they were just a few years ago. New regulations, created by the International Maritime Organization, aim to improve air quality by limiting pollutants emitted from large ships. The regulations target three air pollutants produced by internal combustion engines and released in vessel exhaust: sulfur oxides, particulate matter, and nitrogen oxides.

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First of two new oil tankers to begin service in Prince William Sound in 2014

Photo of Liberty Bay courtesy of Aker Philadelphia Shipyard.
Photo of Liberty Bay oil tanker courtesy of Aker Philadelphia Shipyard.

The first of two new SeaRiver oil tankers is expected to begin service in Prince William Sound later this year.

SeaRiver, the shipping arm of ExxonMobil, held a naming ceremony for the vessel Liberty Bay on April 25. The second vessel will be named Eagle Bay.

Built by Aker Philadelphia Shipyard, Inc., both vessels measure 823.5 feet long and 144 feet wide, and have double hull protection for both cargo and fuel tanks. The vessels are capable of carrying 115,000 tons of weight including cargo, fuel, ballast water, provisions and crew. Cargo capacity is 800,000 barrels (approximately 33.6 million gallons). Propelled by a slow speed diesel engine, the vessels’ “service speed” is 15 knots (approximately 17 miles per hour).

Ballast water treatment technology

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Council study reviews escort tug technology

Council Project Manager

This vessel, the Tan'erliq, is an "enhanced tractor tug," or ETT.
This vessel, the Tan’erliq, is an “enhanced tractor tug,” or ETT.

A recent council study found that the escort tugs being used in Prince William Sound, though exceedingly capable, no longer represent the best technology being used for these types of applications and services worldwide.

Loaded oil tankers transiting the waters of Prince William Sound are required by federal law and their oil spill contingency plans to be accompanied by two escort tugboats. Currently, escort tugs can serve in a primary or secondary role, depending on performance requirements established in the tanker contingency plans. The goal of the escort tug system is to prevent an oil tanker that suffers a mechanical or propulsion issue from running aground.

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