After one year in service, Washington State Ferries’ 64 car ferry Chetzemoka has developed hairline cracks in its propellers, potentially from improperly cast stainless steel.
The problem became public knowledge when State Rep. Larry Seaquist, touring Dakota Creek Industries in Anacortes, Wash., noticed the ferry on a lift with its propellers off and asked what happened.
According to a report in the Kitsap Sun, Dakota Creek dry-docked the ferry for scheduled installation of rub rails. An inspection by Washington State Ferries inspectors found hairline cracks in one propeller. A dye test showed each of the five blades was cracking near the hub. The other propeller was checked and had the same problem.
The 7,850 lb, 90 inch diameter fixed pitch propellers were removed and sent to Sound Propeller in Seattle for analysis and repair. A metallurgical analysis concluded they were cast incorrectly, the newspaper quotes a Dakota Creek official as saying. The carbon content of the stainless steel was too high.
The propellers are being repaired and will be used until replacements can be made, which takes 22 weeks, the Dakota Creek official is quoted as saying.
The newspaper says that Washington State Ferries will pursue a warranty claim for two new propellers against the Chetzemoka’s builder, Vigor Shipyards, while Vigor will probably seek a remedy from propeller builder Rolls-Royce Marine.
The newspaper quotes Vigor spokesman Steve Hirsh as saying: “We’re looking at (the problem), Rolls-Royce is looking at it. Between us and Rolls-Royce we will work with Washington State Ferries to see that it is rectified.”
November 11, 2011