(Photo tweeted this afternoon by @wsferries)

A special delivery will be heading to Vigor on Harbor Island tonight. Here’s the announcement from Washington State Ferries:

Ferry commuters are one step closer to a more reliable system as Washington State Ferries celebrates a major milestone for the Chimacum, the fleet’s third Olympic Class vessel. The Chimacum’s 1,110 ton superstructure, which took 18 months to construct at Nichols Brothers Boat Builders on Whidbey Island, will transit to Seattle tonight, Wednesday, April 6.

The announcement continues after the jump:

The superstructure, which makes up the “top-half” of an Olympic Class ferry, will leave Whidbey Island by barge around midnight and transit overnight, arriving in Seattle early Thursday morning. Night owls can track its progress online by way of the Chimacum’s tug, Ocean Mariner, on MarineTraffic.com. Morning commuters and other early risers might catch a glimpse in person when it transits through Elliott Bay on its way to Vigor Shipyard on Harbor Island.

Once the superstructure arrives at Vigor, the new ferry will begin to take shape. The Chimacum’s superstructure will be joined to its hull, a similar process to that shown in a time-lapse of the first Olympic Class ferry, Tokitae, under construction in 2013. The joining process is expected to begin on Friday and take approximately 12 hours.

“The joining process requires remarkable craft and precision,” said Matt Von Ruden, WSF Director of Vessels. “We’re excited because joining the superstructure to the hull moves us one step closer to completing the Chimacum and seeing much-needed new ferries in service to modernize our fleet.”

The 144-car Chimacum is the third Olympic class vessel custom built for Washington State Ferries and will operate on the Seattle/Bremerton route beginning in early 2017. The first Olympic class vessel, Tokitae, joined the Mukilteo/Clinton route in June 2014. The second, Samish, was put into service on the Anacortes/San Juan Islands route in June 2015. Construction of the fourth, Suquamish, is just beginning at Vigor. It is scheduled to enter service in early 2019.