Report: Yorktown repair estimate less than feared

The World War II-era Yorktown aircraft carrier at Patriots Point Naval & Maritime Museum requires significant repairs to its rusting hull and other parts of the ship.

The cost to repair the main attraction at Patriots Point won’t be cheap, but it’s dramatically cheaper than previous estimates.

Collins Engineers performed a structural assessment on the 888-foot-long Yorktown warship from February to November. It gave its final report to the Patriots Point Development Authority at a board meeting Friday.

The firm estimated it will cost about $40 million to restore the rusting World War II-era aircraft carrier. Previous projections have been as high as $100 million.

“We knew there were issues, so this now gives a section-by-section blueprint of what’s wrong and what needs to be done,” said Mac Burdette, executive director of the Patriots Point Naval & Maritime Museum in Mount Pleasant.

Jonathan Sigman, a senior project manager with Collins Engineers who oversaw the Yorktown project, said there were no public safety issues or concerns about the structural stability of the ship.

He added that the engineering staff at Patriots Point has done “a proper job of making sure problems are maintained and making sure the ship remains in working order and safe for the public.”

But considering areas around the hull and the bow that have deteriorated by 25 percent or more, the report recommends that the state-owned tourist attraction start implementing a repair plan within five years.

The most pressing problems are in the bow, where flooding has led to significant damage. The museum staff has known about those issues, so the assessment team focused on inspecting about 100 areas behind the bow from inside and outside.

The hull, where most of the corrosion was expected, has deteriorated by about 3 percent below the waterline, which is relatively low, Sigman said.

At the splash zone — a roughly 6-foot-tall band around most parts of the ship that are exposed to waves — the steel plates had generally corroded by about 10 percent to 15 percent. Some isolated areas were more significantly damaged and had holes about an inch in diameter, Sigman added.

“We chose to inspect areas where we were most likely to find high corrosion, and since there was such low corrosion, we feel pretty comfortable saying we would find similar results around the rest of the frame,” he said.

The engineering firm’s $40 million cost estimate doesn’t include the price of a cofferdam, which would be needed for shell plating repairs below the waterline.

The assessment itself cost the museum $554,000, and other expenses must be funded before any structural improvements can be made.

In 2013, another group of specialists inspected the ship for environmental hazards that would have to be dealt with.

For instance, the fuel tanks that sit behind all the steel plates that need to be replaced need to be cleaned thoroughly so petroleum residue doesn’t seep into Charleston Harbor. The entire cleanup, which involves many other tasks, was estimated to cost about $4.4 million.

Burdette said lease revenue from future tenants at Patriots Point will help support those costs over time. The museum board is still in negotiations with local hotel developer Mike Bennett, who has agreed to lease the rest of the available land, which is about 50 acres, for a mixed-use project.

Within 10 years, Burdette expects annual lease revenue to increase from $1.5 million to $6 million, which might allow the board to explore alternative financing options.

“If we have $6 million a year that is dedicated to nothing but maintenance of our ships and our piers, then it would be very logical and reasonable to approach the state to issue bonds over a period of time that would be paid by this stream of income,” he said.

He also said the board plans to ask U.S. Sens. Lindsey Graham and Tim Scott for help securing national funds to assist in long-term repair costs.

Reach Abigail Darlington at 937-5906 and follow her on Twitter @A_Big_Gail.