During World War II, Electric Boat built 74 submarines. Those not lost in combat had normal lifespans and then were replaced.

Six of them beat the odds and have survived at maritime museums around the country.

That number may soon drop to five.

The Clamagore, which was launched at EB in 1945, is likely to become the first U.S. submarine to be scrapped after being preserved as a museum ship.

The decision by Patriots Point Naval & Maritime Museum in Mount Pleasant, S.C., comes after years of exploring options for the decaying vessel. The move is being opposed by a submarine veterans group.

Clamagore's fate highlights pitfalls in the still-emerging business of maintaining former naval vessels as public attractions.

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Decades in salt water have taken their toll on Clamagore, said Mayci Rechner, a Patriots Point spokeswoman.

"We've always been fighting that battle since it arrived here," she said, but the problems have worsened in the past decade.

The main ballast tanks are corroding, causing buoyancy problems and posing an environmental threat. The boat contains polychlorinated biphenyls, or PCBs, which must be removed to meet Environmental Protection Agency standards. It also has 504 lead batteries, each weighing 1.5 tons.

While the problems are contained for now, there are worries the boat could sink in a hurricane, Rechner said.

In 2019 the cost of restoration was estimated at $9.35 million, more than the museum says it can afford.

"There is a business element to what we do at Patriots Point," says a Clamagore-related document on the museum's website.

Berthing the sub on land was explored but would cost $5.8 million by a 2010 estimate. Other groups expressed interest in taking Clamagore, but none had enough money, Rechner said.

With no good options, the museum announced March 18 that its board had voted unanimously to start the process of dismantling and recycling the 77-year-old submarine, which is expected to cost $2 million. No timeline has been set.

The Navy has no record of any of the 20 or so submarines it donated to museums being scrapped.

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As Clamagore (SS-343) glided into the Thames River from EB's north yard on Feb. 25, 1945, the conflict it had been built for was almost over. Departing Groton that summer for the Pacific and its first war patrol, Clamagore had only reached the Panama Canal when hostilities ended.

So while of World War II vintage, it's more of a Cold War artifact. Like other Balao-class subs, which were built in huge numbers, it underwent postwar modernizations that improved its capabilities and changed its appearance. Twice Clamagore was upgraded under the Greater Underwater Propulsion Power, or GUPPY, Program.

In 1948 it became a GUPPY II, which left it with a rounded bow and a two-level "step sail" in place of its original conning tower. In 1962 it was converted to a GUPPY III, with a taller "North Atlantic" sail and a 15-foot hull extension. Clamagore was one of only nine GUPPY IIIs and is the last one in existence.

After its final 12 years of service, when it was based in Groton, Clamagore's 1975 decommissioning marked a milestone. Two decades into the nuclear era, Clamagore and another boat, which was retired the same day, were the last diesel submarines based in Groton, ending an era dating to World War I.

Instead of being scrapped or sold to a foreign navy, Clamagore was donated in 1979 to Patriots Point. For four decades it sat alongside two other World War II ships, the aircraft carrier Yorktown and the destroyer Laffey.

During that time the sub was named a National Historic Landmark. The nomination form notes that as the last GUPPY III, Clamagore "represents the ultimate use and technological adaptation of war-built diesel submarines by the Navy."

The document, written in 1988, calls Clamagore "a well-preserved vessel."

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Around that time is when William Bryar started questioning aspects of Clamagore's maintenance. Bryar, who lives a half-hour from Patriots Point, served on the sub in Groton from 1970 to 1975.

He was in a group of volunteers, mostly retired or active-duty submariners, who helped keep Clamagore in shape.

Bryar believes Patriots Point was never committed to preserving the sub and has inflated the cost of restoration. He said he formed the Clamagore Restoration and Maintenance Association, or CRAMA, a decade ago when the museum considered sinking the boat as an artificial reef.

The mission of the group, which has about 4,000 members, is to save Clamagore and either relocate it or help maintain it where it is, Bryar said.

In 2019, CRAMA sued Patriots Point, arguing that the museum has a poor record of maintaining historic ships, that it lacks authority to scrap Clamagore, and that doing so would violate state law.

A judge in South Carolina's Ninth Circuit Court of Common Pleas dismissed the suit, ruling CRAMA did not have standing to sue, said Nancy Bloodgood, CRAMA's lawyer. She filed a motion to amend and said Patriots Point is proceeding with the disposal while the sub is under litigation.

Rechner said the case was dismissed and declined to comment further.

Under the Navy's Vessel Donation Process, in effect since 1948, the title is transferred to the recipient, according to the Naval Sea Systems Command in Washington. The arrangement is subject to terms of a donation contract.

Separately, the National Historic Preservation Act requires the Navy to assess how actions such as disposal would affect historic properties. At Patriots Point's request, the Navy conducted that assessment and in 2019 consented to the dismantling.

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While Clamagore would be the first U.S. submarine museum ship to be scrapped, other vessels have met that fate, including the aircraft carrier Cabot and several British and Soviet submarines.

The business of preserving naval vessels as museums is relatively new, dating to the 1940s, said Ryan Szimanski, executive director of the Historic Naval Ships Association, which links museums with about 170 historic vessels worldwide.

"We're still learning how long we can maintain ships like these," Szimanski said. "We made a heck of a lot of mistakes."

For instance, the battleship Texas, berthed near Houston, was flooded and sunk into the mud for fear a hurricane could drag it to sea, he said. The result was holes in the hull from decades of sand washing against it.

"These ships are artifacts just like you would see behind glass in a regular museum, but they're the size of an office building," Szimanski said.

Though one is occasionally scrapped, it's more common for a museum to acquire a vessel and face so many expenses the project never gets off the ground, he said. Then the ship is returned to the Navy.

That's similar to what happened with Croaker, another EB-built sub from World War II, which was open to the public in Groton from 1977 to 1987. Because restoration standards under the donation contract were expensive, the museum operator asked the Navy to take it back. Croaker is now in Buffalo, N.Y.

The other remaining wartime subs built by EB are Becuna, in Philadelphia; Cavalla, in Galveston, Texas; Cobia, in Manitowoc, Wis.; and Cod, in Cleveland. Two later survivors are Marlin, launched in 1953 and now in Omaha, Neb.; and Nautilus, the first nuclear submarine.

Nautilus is undergoing a $36 million preservation project by EB at the Naval Submarine Base in Groton. The work includes repairs to the hull and superstructure, replacement of topside decking and upgraded lighting and electrical work.

It's expected to return to the Submarine Force Museum in August and be open by September, said Chris Zendan, a base spokesman. The repairs should help Nautilus last another three decades.

Szimanski said it remains to be seen how long older vessels can be maintained, since they were built to be scrapped after 20 years. World War II-era ships, all around the same age, may be nearing the end of their lives, he said. On April 14, the destroyer The Sullivans suffered a hull breach and partly sank in Buffalo.

While some ships can be preserved indefinitely with money, he said, others struggle to attract enough support.

For Clamagore, time has almost run out.  The sub closed to the public in December, but Patriots Point has allowed former crewmen to return for a final tour, Rechner said.

The museum is identifying parts to salvage and display, including sonar equipment, torpedo hatches and the periscope. The exhibit will be housed on the Yorktown.

What's left of a submarine lost to the ravages of time will be preserved on a ship that's two years older and vastly larger, with maintenance needs of its own.

j.ruddy@theday.com