The safe and steady passage.

• Author: Bonham, Nicole A.
• Position: Tugboat escort service for oil tankers

From the terminus at the southernmost point of the 800-mile Trans-Alaska oil pipeline, tankers fill their bellies with the oil that fuels the world's progress, then transit from Prince William Sound into the Gulf of Alaska and some of the wildest weather and waters on earth.

Yet, the most dangerous leg is well before the tanker reaches open water. Rather, the touchiest part of the trip naturally occurs as the laden tanker navigates its way from the Valdez terminal to the open arms of Seal Rocks and the wide Gulf beyond.

According to Gene Till, operations advisor for Alyeska's Ship Escort/Response Vessel System (SERVS), as an oil-laden tanker leaves Port Valdez, it transits through the Valdez Narrows to the end of Valdez Arm-all the while with a tug tethered to its stem. In close proximity is a separate emergency-response vessel (ERV). The multi-faceted vessels are designed to aid tankers with power or maneuvering problems, and to respond in the event of a spill. The tugs carry appropriate equipment and have the ability to recover oil and store it, according to Alyeska.

"The mission of those two vessels is to safely escort a laden tanker through a traffic zone," Till said.

Once the flotilla passes what's called Buoy Nine at the mouth of the Valdez Arm, the tug untethers from the stern of the tanker and increases speed, all the while transiting toward Hinchinbrook Entrance and the mouth of the Sound.

From there, a 10,000 horsepower rescue tug relieves the primary escort tug and accompanies the tanker, standing by until it reaches Seal Rocks, a point some 17 miles out of Prince William Sound.

"It stands by there unless something goes wrong as the tanker approaches the Gulf," Till said. "The ERV also stands by."

It's a process that's aided by constant radio communication and radar tracking, with the very makeup of the waterways requiting steady seamanship.

The Valdez Narrows is characterized as a narrow channel with a rock in the middle, and a one-way traffic...