The Cable Innovator arrived in Wrangell on Sunday for a week-long project to relocate about 14 miles of GCI fiber optic cable to a new route on the south side of Woronkofski island. The work included trenching the beach near Shoemaker Bay (above) to run the cable ashore to a new connection point. The specially built ship for cable-laying work serves West Coast telecommunications companies.
A ship built especially for laying fiber optic cable on the ocean floor was in front of Wrangell this week, moving GCI's Seafast communications cable into a safer position away from underwater power lines and the risk of sediment avalanches.
The 477-foot-long, 78-foot-wide Cable Innovator, built in a shipyard in Helsinki, Finland, in 1995, will relocate about 14 miles of cable from its old starting position near Cemetery Point in Wrangell. From there, it wrapped around and down the west side of Woronkofski Island and south through Stikine Strait on its way to Ketchikan.
The new route will begin near Shoemaker Bay and run through Chichagof Pass, south of Woronkofski, to link up with the line to Ketchikan, connecting Wrangell's internet traffic worldwide.
From Wrangell, the telecommunications cable runs to Petersburg.
"We are moving our cable so SEAPA can do its work," said Bruce Rein, senior staff engineer at GCI. The fiber optic cable crosses the Southeast Alaska Power Agency's lines at a 90-degree angle, just off the northwest end of Woronkofski Island, Rein said.
SEAPA needs to repair a section of its line between Woronkofski and Vank Island, on its route between Wrangell and Petersburg, and the power agency had requested that the communications company move its cable out of the way, according to a relocation plan GCI filed with the state last year.
GCI has two fiber optic cables serving Wrangell, and the temporary loss of one line this week should not affect service, Rein said.
In addition to getting the cable out of way of power lines, the operation is intended to move the line out of the danger zone of underwater sediment avalanches, Rein said. Strong earthquakes can dislodge seafloor sediment, he explained, damaging cables, such as in January 2013 when a 7.5 earthquake struck 70 miles west of Craig, causing breaks in GCI's cable near Wrangell and cutting service.
All the sediment carried down the Stikine River builds up on ledges and a quake can dislodge it, Rein said. "It cuts very much like a powder blast of a snow avalanche," he said. Routing the line on the south side of Woronkofski, farther away from the river, will help avoid that risk.
The Cable Innovator arrived offshore Wrangell on Sunday and among its first tasks was to locate the cable near Cemetery Point, cut it and start pulling the line aboard the ship, Rein said. Because they know the exact coordinates from repair work after the quake, they were able to find the cable. If not, the ship has a remotely operated vehicle it can send underwater to find a line.
After checking the 1.25-inch-diameter cable for anything that needs repair, the ship will re-lay the line along its new route.
The Cable Innovator lays out line from its stern, unwinding the feed from a large drum that can hold 8,500 tons of cable.
The ship was offshore Shoemaker Bay on Monday, and the work went well, Rein said. The cable was floated to shore and connected to a pre-installed beach cable vault and secured. "The submarine cable will be spliced to GCI terrestrial cable at this point," according to the company's filing with the state, tying back to near Cemetery Point to feed the underwater line to Petersburg.
The ship was in Stikine Strait on Tuesday, pulling more cable to re-lay in Chichagof Pass.
The work should finish before the weekend, "talking a perfect world," Rein said. Much will depend on whether repair work is needed on the line after it is pulled onboard the ship and inspected, he said. A full splice of the line can take 18 to 24 hours.
The Cable Innovator works exclusively on the West Coast and sailed to Wrangell from Victoria, British Columbia, where it was on standby for such repair work, Rein said. The ship is shared by several telecommunications companies, and is on-call 24 hours a day year-round.
The ship's specs say it is powered by diesel-electric engines built by Wartsilla, with a combined power of almost 13 megawatts. Its engines drive a single shaft propeller, with two bow thrusters and two at the stern.
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