Answering the questionsBarrett responds to issues raised about the transition at Valdez Marine Terminal
Alan Bailey Petroleum News
During a presentation to the House Resources Committee on Feb. 7 Tom Barrett, president of Alyeska Pipeline Service Co., commented on some concerns that have been raised regarding the transition of marine services at the Valdez Marine Terminal from Crowley Marine Corp. to Edison Chouest Offshore. The marine services operations provide tanker escort services in Port Valdez and across Prince William Sound, as well as oil spill response services for the tanker and terminal operations. When Edison Chouest takes over the service in July the company is bringing a fleet of brand new, purpose-built tugs and response barges. Concerns have been expressed over some aspects of the tug designs and over the weather limits for tanker operations.
Model testing A tug design concern, which came from a report from a marine architect that Prince William Sound Regional Citizens’ Advisory Council had commissioned to assess Edison Chouest’s new fleet, questioned the lack of scale model testing of the vessels, to verify that the tugs could handle anticipated sea conditions in Prince William Sound. Barrett told House Resources that the tugs’ designers had used a computer-based design methodology, a methodology that is becoming standard practice and that is more accurate than model testing. However, in response to the concerns raised, Alyeska ordered model testing of the designs, Barrett said. He said that he had not yet seen a report from this testing but that he had not heard anything to suggest that the designs were flawed.
Bow thrusters Another issue arising from the marine architect’s report concerned the lack of bow thrusters in the tug designs. Bow thrusters can improve a vessel’s maneuverability. Barrett said that Alyeska had talked to a number of marine architects about this and that the decision not to install thrusters related to the anticipated operational speed of the tugs. While the lowest escort speed in Prince William Sound is six knots, the thrusters are useful up to around two knots. And at the higher speeds the presence of the bow thrusters could reduce the effective power of the vessels’ drive systems, thus reducing the tugs’ abilities to respond to an emergency, Barrett said.
Weather limits With respect to weather limits, on Jan. 18 the board of PWSRCAC passed a resolution stating that the limits for tankers crossing Prince William Sound should be no more severe than weather and sea conditions used for escort tug drills and training. In other words, if conditions are too dangerous for tug drills and training, conditions are too dangerous for tanker operations, the board said.
Tankers are not allowed to transit the sound when wind and wave conditions exceed certain criteria. However, in the interests of tug crew safety, Alyeska does not conduct training exercises in these limiting conditions.
Barrett told the committee that, while he respects the experience and knowledge of PWSRCAC board members, he disagrees with them with regard to this issue. The purpose of training and drills is to perfect techniques and build capabilities, without putting people into unacceptably dangerous situations, he said. Barrett, who is a retired U.S. Coast Guard admiral, said that the Coast Guard, one of the premier lifesaving services in the world, does not train its personnel in the extreme conditions encountered in some of the agency’s rescue missions. Fire fighters do not train in burning buildings and are not allowed to train in uncontrolled conditions, he added.
Barrett likened the training of tug crews in marginal weather conditions to teaching someone to change a tire on a freeway, rather than at home on the driveway. The fact that the person has not changed a tire on a freeway does not make freeway driving dangerous, he said.
The tankers using the Valdez Marine Terminal can safely transit Prince William Sound within the prescribed weather limits, Barrett said. But conducting exercises in heavy weather - perhaps tethering a massive tanker following a simulated engine failure - would significantly up the risk ante.
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