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Gargantuan may be the best description for a 960-foot-long ship-servicing dock that arrived in three pieces last month at Vigor Industrial鈥檚 Portland shipyard.

The word also aptly characterizes efforts to transport, assemble and install the Chinese-made floating dry dock, called the Vigorous, in time for it to open in November. Planning began 18 months ago for the $50 million project to build the largest dry dock in the U.S. It will allow Vigor Industrial workers to maintain and repair larger ships that weigh up to 80,000 tons.

鈥淚t鈥檚 a big task to get this put together and in service,鈥� said Mike Nutter, a senior project manager for Vigor Industrial. 鈥淓verybody is in a hurry to get it going. The big thing for us is doing it safely and making sure we鈥檝e got a plan.鈥�

In late August, the three massive dock pieces arrived in Portland from China, stacked aboard a heavy cargo ship longer than 700 feet long. Work is under way to weld the pieces together and hook up the control system. Tugboats will then move the dry dock to its final location at the Vigor Industrial shipyard where it will be connected to ramps and gangways. The process also involves moving two existing dry docks to make room for the Vigorous.

When the Vigorous is up and running this fall, shipyard workers will use valves to let water into the U-shaped dry dock, submerging it so that ships can enter. When water is pumped out, the dock will rise and lift the ships to accommodate repairs.

Assembling the dry dock is essentially like building a ship without a motor, Nutter said.

鈥淭his isn鈥檛 uncommon work for us,鈥� he said. 鈥淭his is what we specialize in. It鈥檚 really dealing with the size of it. We鈥檙e not used to dealing with something this large.鈥�

A bigger dry dock that can accommodate a crane will help Vigor Industrial meet the demand for maintaining and repairing military, cargo and cruise ships that continue to increase in scale, Nutter said.

鈥淭here are a lot of vessels that are getting bigger, and it was a right time,鈥� he said.

Currently, the shipyard can repair ships that weigh up to 25,000 tons, but demand is so high to service heavier ships that Vigor Industrial already has two military cargo ships waiting on-site for maintenance on the Vigorous, said Ken Swingle, facilities director for Vigor Industrial.

The challenge was preparing the shipyard to accommodate a much larger dry dock designed by Holliston, Mass.-based Heger Dry Dock Inc., he said. In a domino effect, two of the yard鈥檚 three existing dry docks will be relocated and then reconnected to the shore, Swingle said.

To help with this process, Vigor hired Portland-based civil and structural engineering firm WDY. The firm engineered gangways that will connect to one of the existing dry docks that will be moved to accommodate the Vigorous. The Vancouver, Wash. office of WorleyParsons designed a pier that will attach to the relocated dry dock.

The trickiest part of engineering the two steel-truss gangways that will attach to the relocated dry dock was factoring in the marine environment, WDY principal Doug Paola said. The ramps will be attached to the dry dock with hinges so they can move vertically and horizontally with the fluctuation of river levels, he said.

Careful planning by engineering firms like WDY should pay off with smooth relocations of the existing dry docks, Swingle said.

鈥淲e have to figure out how to reconnect it,鈥� he said. 鈥淭here were a lot of engineering firms involved. That鈥檚 what I鈥檓 nervous about is when we pull it in with the tug(boats), it better fit.鈥�