PORT TOWNSEND — The newly constructed MV Chetzemoka ferry could be in service on the Port Townsend-Whidbey route in October, the state ferries system said Thursday.
A problem with excessive propeller vibration at high speeds has been eliminated, it said.
The ferry’s Port Townsend debut, which had been scheduled Aug. 29, was postponed after the vibration was detected last month.
Last week, Washington State Ferries said a change in the software program that controls the propeller system was expected to prevent the engine from overpowering the propeller used to stop the vessel — and stop the vibration.
Thursday, the agency said that the change had eliminated the unwanted vibration.
The announcement followed eight hours of sea trials in Keystone harbor on Wednesday.
“We believe we have resolved the issue of vibrations,” said David Moseley, assistant secretary for Washington State Ferries, in a statement.
The state ferries system will take formal possession of the 64-car ferry sometime next week, which will signal the beginning of a crew-training period scheduled to last at least six weeks, said Marta Coursey, state ferries system spokeswoman.
Captains, engineers and crews will become familiar with this new class of ferries, to continue testing its operating capabilities and to practice a variety of emergency and security drills, the state ferries system said.
Coursey would not commit to an exact date, but estimates that boat will be in service sometime in October.
Both Port Townsend and Coupeville have planned inaugural celebrations for the ferry, which Gov. Chris Gregoire is expected to attend.
In previous trials, engineers had determined that the vibration occurred as the ferry pulled into the Keystone Harbor on Whidbey Island. The ferry had to generate enough power to cross Admiralty Inlet and then slow quickly to dock safely.
The ferry was not able to accomplish this without causing excessive vibration at high speed.
Refinements to the propulsion-control system software, tested in eight hours of sea trials Wednesday, provided greater control over engine “ramping,” which allows the bow propeller to slow the ship as it approaches the dock, the state ferries ssystemsaid.
Now, the propeller speed is gradually ramped up, as opposed to a more sudden and quick thrust of power, which eliminated the unwanted vibrations.
“In working with [manufacturer] Todd Shipyards, we fine-tuned and refined the operating system to ensure that the propulsion components work together for optimal performance,” Moseley said.
“We have a boat that we’re confident meets our operating requirements, can stop in the required distances and will provide safe and reliable service.”
The Chetzemoka, budgeted at $76.5 million, and a second ferry, the Salish, will replace the 80-year-old Steel Electric ferries that Transportation Secretary Paula Hammond pulled out of service in late November 2007, saying the vessels were unsafe.
Since then, the 50-car ferry Steilacoom II, which the state leases from Pierce County, has sailed the route alone.
The Salish is expected to join the Chetzemoka on the route in spring 2011.
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Jefferson County Reporter Charlie Bermant can be reached at 360-385-2335 or charlie.bermant@peninsuladailynews.com.
