MANITOWOC (NBC 26) — The USS Cobia developed a noticeable lean during SubFest weekend, caused by rainwater seeping through a rusted vent into a ballast tank.
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Hundreds of visitors toured the USS Cobia at the Wisconsin Maritime Museum in Manitowoc over the weekend during SubFest, an annual celebration of the city's submarine-building history — but some may have noticed the historic vessel leaning to one side.
Karen DuValle, the museum's submarine curator, said the cause is rainwater collecting inside a ballast tank after seeping through a rusted vent.
"The sub was listing as we call it, leaning on the starboard side which is on the river," DuValle said.
Crews pumped out some of the water before SubFest. The museum now plans to patch the vent.
"This has happened before on other ballast tanks, this one just happens to be collecting more and causing it to lean," DuValle said.
The Cobia was in dry dock last fall for maintenance, but the rusted vent was not found during that work. Staff first noticed the lean in April and said it took time to identify the source of the problem.
When asked what could have caused someone to miss the issue, DuValle said the location of the vent made it easy to overlook.
"Partially the location that it is in, unless you were really specifically looking for it. It got missed, it's an old boat, things rust," DuValle said.
The museum says the lean is not a safety issue.
SubFest drew about 600 visitors to tour the USS Cobia over the weekend — far more than the 80 to 120 visitors the submarine typically sees on a Saturday. The event celebrates the 28 submarines built in Manitowoc, honors the USS Cobia, and recognizes veterans and active duty military.
Jozlyn Michalek, the museum's visitor engagement supervisor, described what the event means to the community.
"SubFest is a celebration held at the Wisconsin Maritime Museum typically celebrating the 28 submarines built here in Manitowoc, we also celebrate the USS Cobia... we also honor our veterans and active duty military," Michalek said.
The museum says the submarine will be patched at some point this summer. Visitors will still be able to tour the Cobia even while repairs are underway.
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