Rudder cracks found in new double-hull tankers

During a routine inspection on May 14, 2005, of the Alaskan Frontier, a new double-hull tanker that hauls crude oil for BP, divers discovered a nine-foot crack on one of its twin rudders. Other cracks were subsequently found on the other rudder. A second, newer BP ship made by the same manufacturer and to the same specifications, was then also checked for rudder damage, revealing that it, too, had smaller cracks in one of its twin rudders. The largest crack on that vessel, the Alaskan Explorer, is 15 inches.

The cause of the cracks is unknown. According to Anil Mathur, president of Alaska Tanker Co., a detailed analysis is being conducted and the results should be available within the next couple of weeks.

Each of the steel rudders measures about 30 feet high by 18 feet wide. Mounted behind the ship’s propellers, they are the only means of steering the tanker. Both ships have been in service less than one year.

The Alaskan Frontier is expected to be out of service for several weeks while it is repaired. As of May 20, temporary repairs had been made to the Alaskan Explorer; it arrived in Valdez and began loading crude oil on May 25. The vessel departed on May 26.

Normally, only laden, outbound tankers require tug escorts through the sound. However, as a precautionary measure, the American Bureau of Shipping (ABS) is requiring the Explorer to have a close escort in “pilotage waters,” even while empty, until a detailed analysis of the crack is complete and permanent repairs are made. According to Tom Colby of Alaska Tanker Co., “pilotage waters” for Prince William Sound is from the pilot station (by Rocky Point just north of Tatitlek Narrows) to the Valdez Marine Terminal. The existing sentinel escort system for Hinchinbrook and central Prince William Sound is considered adequate, and a close escort inbound for these areas is not necessary. The existing outbound escort system has also been deemed adequate and no changes are required.