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Tokitae

Nov 5, 2014 03:36 PM

Charting a new course for Washington State Ferries

Courtesy Washington State Department of Transportation

The christening of Tokitae at the Vigor Fab shipyard in Seattle last spring was a milestone for Washington State Ferries (WSF), culminating a decade of work with the first of a new Olympic class of ships.

The preliminary design process for this 362-foot, 144-car ferry began in 2004 with the goal of replacing the 87-car Evergreen State — built in 1954 — before it was 60 years old. Seattle-based Guido Perla & Associates was awarded the design/build contract and was working on detailed engineering plans when severe hull corrosion was found in four of WSF’s smaller ferries in November 2007.

Because of budget constraints, WSF was fitting new stern tubes in the 60-car Steel Electric class, built in 1927, hoping to further extend their life. All four ferries were declared unseaworthy and immediately pulled from service. A 50-car, county-owned ferry was chartered to maintain the Whidbey Island to Port Townsend route on a reduced schedule, and the Olympic class was shelved (the Steel Electrics were finally scrapped in Ensenada, Mexico, in 2010).

Tokitae, shown in dry dock at Vigor Fab, is the first Olympic-class vessel for Washington State Ferries. The name is a Coast Salish greeting that means “nice day, pretty colors.”

Courtesy Washington State DOT

WSF’s director resigned and David Moseley, a civil service manager, took the position and began reviewing the agency’s long-term planning. “This is a big job with big challenges,” he said. With the loss of capacity, the state provided funds in February 2008 for an expedited  program to build three 64-car ferries.

To comply with a 1993 state law, the vessels had to be built in Washington. To speed the process, a proven design from Elliott Bay Design Group of Seattle was selected — the ferry Island Home was already operating on the Woods Hole to Martha’s Vineyard run in Massachusetts. The length was increased to 273 feet and work began early in 2009 using construction engineering and design by Guido Perla.

Todd Shipyard of Seattle was the prime contractor, but much of each ferry was prefabricated off-site: the superstructures at Nichols Brothers on Whidbey Island and the bows at Jesse Engineering in Tacoma. The first hull, Chetzemoka, entered service in November 2010 — three years after the Steel Electrics were pulled. With the second vessel well underway, Todd was acquired by Vigor Industrial of Portland, Ore. Production continued without interruption and the third vessel was delivered in February 2012.

With this success, WSF returned to the Legislature to fund the Olympic-class design, which would enable the agency to introduce a maximum 60-year service life throughout the fleet. After a heated political debate, $265 million was approved for construction of two 362-foot vessels. The Olympic class is considered a midsize ferry compared to the 460-foot Jumbo class that carries more than 200 cars.

The helm includes two jog sticks, one for each rudder, that operate a rotary vane steering system. The forward rudder is locked while the ferry is underway and the forward propeller is feathered. The throttle levers are combined with the propeller pitch control.

Peter Marsh

Vigor was the prime contractor, with the same team of subcontractors plus Greer Tank & Welding, which built all the tanks. Guido Perla produced the detail engineering design, assembly and CNC cutting files, while Vigor began work on the fabrication and production.

Construction began on the first hull, Tokitae, in early 2012. The hull was assembled from 10 modules at the Vigor Fab shipyard and is classed Subchapter H for 1,500 passengers by the U.S. Coast Guard. Construction is to ABS standards: bottom plating is 7/16-inch steel and the superstructure is 1/4-inch to 5/16-inch steel.

Brian Evert, Vigor Fab’s director of project management, explained that the standard shape of the hull ends was refined by tank tests to include a more streamlined “wake-adapted” stern. The narrow tapered cross-section required the use of special castings for the stern tube and protective skeg, with tight frame spacing and heavily rolled plating. The specification included high-lift rudders produced by Rolls-Royce.

Tokitae is powered by two 3,000-hp EMD 12-710G7C diesels that meet EPA Tier 3 requirements for 2014 without after-treatment. The engines face in opposite directions, each connected to one Rolls-Royce controllable-pitch, four-blade propeller via a Falk 4.986:1 reduction gear. An interconnecting shaft runs between the transmissions, allowing both engines to power a single aft propeller for a top service speed of 17 knots at 80 percent power.

The superstructure is more than 300 feet long, weighs 1,500 tons and includes four upper decks: the upper vehicle deck, passenger deck, sun deck and crew-only navigation deck. To load the massive module onto a barge bound for Vigor, heavy lift contractor Omega Morgan laid a platform 600 feet across a road, beach and tide flats into Holmes Harbor to reach a depth of 12 feet at high tide.

“The loading procedure is slow, methodical and must be very precise. Having to make adjustments is not unusual,” said Matt Nichols, CEO of Nichols Brothers.

The first slide-out took two weeks, but the second took only two days. The tow to Harbor Island in Seattle lasted six hours. Matching the position of the superstructure to the bare hull — each on separate dry docks — demanded the laying of 600 feet of track, meticulous work with buoyancy controls, and the use of a hydraulic transfer system designed by Engineered Heavy Services.

Tokitae has four passenger evacuation systems with inflatable slides that lead into extra-large SOLAS life rafts.

Courtesy Washington State DOT

Interior improvements over older WSF vessels include wider vehicle lanes, two ADA-compliant elevators and wider stairwells. The sun deck has overnight cabins for crew who are working the early shift.

To abandon ship, there are four evacuation systems from Liferaft Systems Australia. Located on the passenger deck in large lockers, they inflate to provide slides leading into extra-large SOLAS inflatable life rafts. Four additional rafts are stowed on the sun deck.

The ferry is operated from identical wheelhouses at each end connected by the walkway on the nav deck. The captain’s station on the bridge is at the port or starboard radar consoles, each consisting of a pair of Furuno radar screens with DGPS/AIS overlay, full Internet connectivity and a voyage data recorder.

The helm consists of two jog sticks set fore and aft on the dash — one for each rudder — operating a rotary vane steering system. When underway, the forward rudder is automatically locked and the forward propeller feathered for minimum resistance. The pair of throttle levers is combined with the propeller pitch control. At very slow speed, the bow rudder and propeller can be activated for maneuvering at the ramp.

In the event of any of these controls malfunctioning, the helmsman also has an electronic order telegraph to signal the engineer on duty in the engine room to override the system manually.

The ferry is operated from identical wheelhouses with twin Furuno radar displays.

Peter Marsh

The keel for the second Olympic-class ferry, Samish, was laid at the end of 2012 with delivery scheduled for early 2015. State lawmakers approved funding for a third ferry, then Moseley unexpectedly resigned after Tokitae was christened.

“That’s six new ferries built, under construction or funded in just six years,” he said. “Finally, the average age of our ferry fleet is going in the right direction. It is now time for the next person to build on our successes and continue to move the system forward.”

Capt. George Capacci, who took charge of WSF in the interim, presided over the commissioning of Tokitae at the Clinton terminal, with Native Americans, local officials and shipbuilders present. “We have a longstanding, productive partnership in new vessel construction with Vigor,” he said. “I am elated that we have accepted the Tokitae. Vigor and their subcontractors have delivered a good product that will serve our customers for decades to come.”

Tokitae makes the 20-minute Mukilteo/Clinton run to Whidbey Island. Two ferries serve the route, carrying 3 million passengers per year. WSF operates 22 ferries, carrying 22 million passengers and 10 million vehicles annually. It is the largest ferry system in the U.S.

Aug 13, 2015 04:15 pm
 Posted by  Bob F

I was disappointed to see credit for the load-out of the superstructure given to the wrong company. The credit should have been given to Engineered Heavy Services of Everett, Wash. EHS engineered the moves and provided the necessary equipment used at Nichols as well as at Vigor.
– Bob French

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