Technology study demonstrates importance of the Council’s independent research

Photo shows Coast Guard officer firing a messenger shot line from one Coast Guard vessel to another. This is one method of connecting tow lines between a tug and a tanker.
In this 2016 photo, a U.S. Coast Guard officer fires a messenger line from one military vessel to another. This is one method of connecting tow lines between a tug and a tanker. Photo by Pasquale Sena, U.S. Coast Guard.

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)

Genetic testing reveals no new marine invasive species

Photo of settling plate

By Austin Love
Council Project Manager

Council testing plankton genes to supplement existing processes

The Council funds monitoring for marine species that could be introduced into Prince William Sound as a result of the operation of the Valdez Marine Terminal and associated oil tankers. If an invasive species, such as the European green crab, becomes established in Prince William Sound, they could cause serious economic and ecological harm.

Photo of staff member holding a settling plate from a visual monitoring trip.
Council staff member Nelli Vanderberg holds up a plate during a visual monitoring trip in 2019. A series of these plates that are placed in the water in various locations. A closeup of a plate used in visual monitoring is in the header of this page.

To detect potential invasions early, the Council now uses both visual and genetic methods to monitor for potentially damaging species. The Council recently received the final results of the genetic invasive species monitoring conducted in 2017. The DNA of plankton samples analyzed for an extensive list of marine species including but not limited to crustaceans (crabs), mollusks (clams), and annelids (worms). In 2017, using the genetic plankton analysis technique, Council scientists identified 52 marine species in samples from Port Valdez and central Prince William Sound, and none of those were invasive non-native species. However, 2016 genetic monitoring revealed some non-native species in Prince William Sound, the soft-shell clam (Mya arenaria) and a sea squirt (Botrylloides leachii), but those two species were not found in 2017.

The genetic invasive species monitoring method has several advantages over traditional visual identification. Visual species identification is more labor and time intensive; often requiring expert taxonomists for identification and significant time and manual work collecting field samples from the shoreline, seafloor, and water column. Additionally, the costs of visual monitoring can be higher when factoring in travel costs such as airfare and charter boats and paying for personnel to collect and analyze the samples. In contrast, the genetic method does not require expert taxonomists and collecting and analyzing plankton samples is less expensive and labor intensive, compared to collecting samples from various marine microcosms. Another advantage of genetically analyzing plankton samples is that it can simultaneously detect species that live on the seafloor, water column, or intertidal areas because many species have a planktonic larval stage. However, visual species identification is still needed and is used to complement and fill in knowledge gaps left by genetic invasive species monitoring. For example, visual identification would be needed to determine if an invasive species has established a reproductive adult population in a region.

Detailed results of the Council’s 2017 genetic invasive species monitoring can be found in the report:

Metagenetic Analysis of 2017 Plankton Samples from Prince William Sound, Alaska (0.4 MB)

Study evaluates places of refuge

Tanker in Prince William Sound

By Alan Sorum
Council Project Manager

Some locations won’t work for Prince William Sound tankers

A recent Council-sponsored study reviewed eight “potential places of refuge,” or PPOR, which are locations where an oil tanker in distress can anchor and take action to stabilize its condition. Of the eight reviewed in the study, none were found to be safe for use by tankers. However, several safe alternates were identified, analyzed, and proposed for future consideration.

Identifying these sites in advance allows decision-makers to save time during their critical initial response to a potential oil spill. Establishment of these places of refuge is recognized by the International Maritime Organization and other governmental agencies as an important marine safety and pollution mitigation measure.

The Council partnered with the Alaska Department of Environmental Conservation in 2004 to develop a matrix listing potential places a vessel in distress could shelter from weather and rough seas. A review of the department’s website showed that information developed in the 2004 effort has not been updated since it was published.

Technology helped safely evaluate locations

Working with the Alaska Maritime Training Center at AVTEC – Alaska’s Institute of Technology in Seward, Alaska, the Council sponsored development of a high-resolution navigational dataset for Prince William Sound in 2014. This upgraded navigation information, along with AVTEC’s simulators were used to verify the safety of eight sites in Prince William Sound that had previously been identified as PPOR for crude oil tankers.

Beginning in September of 2015, the Council started working with Safeguard Marine, LLC to evaluate the safety of eight of the places of refuge in Prince William Sound. Seven others have already been used by tankers and are known to be safe.

Safeguard Marine evaluated the sites using interviews with local subject matter experts and stakeholders and simulated ship maneuvers. The maneuvers were conducted by members of the Southwest Alaska Pilots Association using models representing Trans Alaska Pipeline System crude oil tankers in varying degrees of distress. Determining whether the PPOR is safe for the oil tanker in distress is a function of whether the vessel could potentially run aground if there is insufficient swing room when anchoring or mooring.

The Council has asked the U.S. Coast Guard and DEC members of the Alaska Regional Response Team to consider the recommendations developed in the study in future updates.

Establishment of preplanned places of refuge provide communities, regulators and industry a chance to consider local knowledge and conditions prior to a crisis. An accurate PPOR matrix provides the Coast Guard Captain of the Port with an additional tool in the decision-making process associated with placing a vessel in sheltered location. Gathering information on potential sites from stakeholders in advance of an incident is always a preferred planning approach and furthers the Council’s stated mission of promoting the safe transportation of crude oil thorough Prince William Sound.


Full report by Safeguard Marine, LLC:

Ship Simulation and Mariner Study of the Maritime Implications for Tank Vessels Utilizing Potential Places of Refuge, Mid-Prince William Sound Alaska (1.4 MB)

Long-term monitoring in Prince William Sound shows lowest contamination levels in study’s history

Photo of Austin Love conducting passive sampling for LTEMP project in 2018.

Results from the Council’s efforts to monitor the long-term environmental impacts of the operation of Alyeska Pipeline Service Company’s Valdez Marine Terminal and associated tankers since the Exxon Valdez oil spill have shown oil contamination in Prince William Sound and the Gulf of Alaska has reached all-time low values. The Council has been conducting environmental monitoring since 1993.

Alyeska and its owner companies have implemented several improvements over the years which have contributed to the reduction of pollutants being discharged. These include the elimination of single-hulled tankers and Alyeska’s ability to effectively operate their Ballast Water Treatment Facility which removes oil contamination from tanker ballast water.

Read moreLong-term monitoring in Prince William Sound shows lowest contamination levels in study’s history

Skip to content