Compass: New and better technology is needed for rig towing vessels
Published: January 16, 2013
By MARK SWANSON
The grounding of Shell Oil's Kulluk drill rig reminds us again of Alaska's tough maritime conditions and our vulnerability from coastal shipping and oil activities in the Arctic and around Kodiak, the Aleutians and Southcentral Alaska.
Rescue vessel crews persevered through a tough response to save the Kulluk. We Alaskans owe a huge vote of thanks to responders who risked lives and equipment to save the rig.
Maritime activities go on constantly, often in weather too rough for meaningful response to accidents. The Kulluk isn't the first vessel to lose power or a tow and be blown ashore in Alaska. It won't be the last. Hand-wringing won't help.
We have to prevent accidents, including additional oversight. Citizen advisory groups like ours could be an important part of that oversight.
The Kulluk incident is an object lesson in the need for best available technology in towing operations and equipment, a lesson that should be applied in Prince William Sound and elsewhere.
Our council, working with the internationally respected naval architecture firm of Robert Allan Limited, completed a study last fall that recommended, among other things, installation of the best available towing technology on the tugs that escort loaded oil tankers through Prince William Sound.
Specifically, the study called for more modern winches that can automatically pay out and reel in tow lines under full load. The winches now on the Sound's tugs represent 15-year-old technology and they lack this capability.
The modern winches recommended by the Allan study permit tugs to apply full towing force and reduce or eliminate the huge tow line surges that come from vessels getting thrown around in big seas. These new winches are designed to help prevent tow line failure by reducing shock loading on the system.
Most towing exercises in the Sound happen in relatively calm weather. The advantages of the new winches do not become apparent until the weather gets rough. With so many successful escorts and exercises behind them, industry and its regulators have grown comfortable with the old-style winches, and they declined to act on our towing equipment study recommendations. Similar recommendations from a study by the international ship classification society Det Norske Veritas a year earlier were similarly dismissed as unnecessary by the industry and the state.
Now, however, we have seen a real-world heavy-weather towing emergency unfold and the results were are not reassuring. The Kulluk incident involved a brand new tug with over twice the horsepower of the Prince William Sound tanker escort tugs, yet it lost its tow line no fewer than five times before the Kulluk grounded near Kodiak. This demonstrates just how difficult towing is in severe Alaska weather.
Bad storms happen all over Alaska, and severe weather just outside of Hinchinbrook Entrance -- where loaded tankers leave the Sound -- is common, more so than in the western Gulf of Alaska where the Shell rig ran into trouble. That's why meteorologists nicknamed the northeast Gulf of Alaska "Coffin Corner."
It's also why loaded oil tankers are not allowed to pass through Hinchinbrook if weather there exceeds 15-foot seas and 45-knot winds. But even that is no guarantee they will avoid extreme conditions. The well-known coastal weather phenomenon called barrier jets often creates high winds and big waves just outside Hinchinbrook, even when the weather inside is much milder.
The questions raised are obvious: What if the Kulluk had been a loaded oil tanker experiencing a loss of power in a storm or a barrier jet along the rugged coast just outside Hinchinbrook? Would a rescue have been possible? What happens around the rest of coastal Alaska when a large vessel loses power and no suitable rescue tug is around?
We don't have answers to those questions, but the Kulluk incident makes a few things clear about what's needed: An ample supply of equipment -- with backups -- for preventing accidents, meaningful oversight of maritime risks and the use of best available technology -- such as towing winches that automatically pay out and retrieve -- in our rough Alaska waters.
Mark Swanson is executive director of the Prince William Sound Regional Citizens Advisory Council.
Read more here: http://www.adn.com/2013/01/16/275525...#storylink=cpy