New corrosion damage has been found on the hull of the SS William A. Irvin, but the museum ship will be back at its berth in Minnesota Slip on Oct. 1 as scheduled.
“It’s not uncommon but we didn’t anticipate it,” said Chelly Townsend, executive director of the DECC, which manages the tourist attraction. “It was a surprise, but we’re working on a solution,” she said at a Wednesday news conference.
A Tuesday news release from the DECC said restoration work exposed concentrated areas of corrosion to the vessel’s hull plates and the rivets that connect them.
“Docked in the Minnesota Slip for more than 30 years, officials attribute the damage to a combination of various factors. The rivets will be assessed by experts this week; a complete plan including scope of work and cost for repairs will be derived thereafter.
There are thousands of rivets on the hull, said Chase Dewhirst of AMI Consulting Engineers, who has inspected the Irvin. Fewer than half are damaged, he said.
“Additional damage to the Irvin includes corrosion of its hull in the form of pitting. Pitting is a common form of corrosion, which has been documented in the Duluth-Superior Harbor. This was the primary motive for the ship’s restoration.”
Because the ship will be in a static display and doesn’t have to withstand wind and wave forces on Lake Superior, its repairs will not have to be as intensive as a working vessel. It must be fit enough, however, to be towed from Fraser Shipyards back to Minnesota Slip.
“This will be in a protected slip. There’s a possibility we won’t do anything with the rivets,” Dewirst said. Fraser has staff qualified to install new rivets, if they are needed.
The Irvinwas squeezed through the Minnesota Slip pedestrian bridge last October with the expectation that it would return to its space in the slip across from the DECC in time for the tourist season this spring. That did not materialize, nor did later estimations of when it might return. It missed the Festival of Sail and will not be in place in time to become the Haunted Ship in October, which nets about half of its annual income.
Part of the delay involved an agreement about what work Fraser Shipyards would be doing on the vessel and what the DECC could afford using funds provided through the Minnesota Historical and Cultural Heritage Grant Agreement with a minor additional match by the DECC.
The museum moved into dry dock Aug. 1 to undergo restoration that included blasting and coating the hull around the waterline, miscellaneous repairs and painting, projected to be completed mid-September. At the time, completion of the work was estimated at four to seven weeks.
The 610-foot, 82-year-old freighter, once the flagship of U.S. Steel’s Great Lakes Fleet, was not primarily moved for repairs and restoration, but needed to be moved to complete the $5.5 million Minnesota Slip cleanup project that included remediation of about 37,000 cubic yards of sediments contaminated with heavy metals and polyaromatic hydrocarbons and repair of the seawall. That project, essentially completed last fall, was jointly funded by the U.S. EPA Great Lakes Restoration Initiative and the Minnesota Pollution Control Agency in cooperation with the U.S. Army Corps of Engineers, the city of Duluth and the DECC. Slip 3, near Pier B, and Slip C, near the former Georgia-Pacific plant and Compass Minerals, in the harbor were capped last fall with clean dredging material armoring stone, according to the EPA.
Since July 13, 1989, the SS William A. Irvinhas been on the National Registrar of Historical Places and so agreement on the full Minnesota Slip project included work with the State Historic Preservation Office about the removal and return of that ship.
“That project technically remains open on the books until the Irvin comes back,” said LaRae Lehto, project manager for the MPCA. “It’s part of our agreement with the city.”
With the Irvinresting in place full-time in the Minnesota Slip, such corrison may not be a surprise. Corrosion of metals within the Duluth-Superior Harbor has been under study since the early 2000s when the extent of is was first discovered by a diver on a routine inspection. The corrosion is widespread, with more than 13 miles of steel sheetpiling covered with pits and some softball-sized holes, according to Wisconsin Sea Grant Institute. Studies concluded that the cause likely was “microbiologically influenced corrosion. “Presence of these micro-organisms results in small physical or chemical differences in the metals or surrounding environment which has been shown to cause pitting, crevice corrosion, differential aeration cells, metal concentration cells, selective de-alloying, increased erosion, and increased galvanic corrosion,” according to a 2010 update on the ongoing study.
The Irvinis not the region’s only museum ship causing concern for its stewards. What to do with the Edna Gtugboat in Two Harbors has been an ongoing concern. The 123-year-old tug is in need of repairs and there has been a debate whether to remove it completely from the water to display it on land or to repair it and return it to a water berth.
The third regional museum ship, the SS Meteor whaleback on Barker’s Island in Superior has been landlocked and buried in stand since it became a museum in 1972. Because it is not floating, and because its exterior is frequently painted, it does not seem to have the same issues with hull corrosion.