CINCINNATI (AP) — The historic riverboat Delta Queen has been nominated to become one of America’s 11 Most Endangered Historic Places.

Landing on the exclusive annual list could save the steamboat from likely decay.

The 82-year-old sternwheeler is scheduled to shut down because Congress has refused to grant another exemption from a federal law that bans more than 50 overnight passengers on boats that are largely made of wood. The exemption expired on Oct. 31.

Owners say the boat, which can carry 176 overnight passengers, can’t survive financially if it can only carry 50 passengers.

So Boone County Historic Preservation Review Board member Don Clare nominated the Delta Queen for inclusion on the list compiled by the National Trust for Historic Preservation. The list raises awareness of preservation efforts.

‘‘The list is very important,’’ said Peter Brink, a senior vice-president of the federally founded and privately funded trust. ‘‘In the 21 years we’ve been assembling the list, we have only lost six places.’’

Sites must meet three criteria — historical significance, urgently threatened and possible solutions — in order to qualify for the list.

Clare noted the boat’s place in history and its current predicament in his nomination.

‘‘This is a great opportunity to call nationwide attention to saving the Delta Queen,’’ said Vicki Webster, the Cincinnati-based leader of the Save the Delta Queen Campaign.

But one nomination doesn’t ensure that the boat will land in the top 11. Supporters of Delta Queen must second that nomination.

‘‘I’ve been on 20 trips on the Delta Queen,’’ said Clare, an emergency room nurse and historian from Rabbit Hash, Ky. ‘‘It’s an American icon like the Statue of Liberty and Mount Rushmore. It is one-of-a-kind. When it’s gone, it’s gone.’’

Built in 1926, the boat is the last operational overnight steam-powered sternwheeler in the United States. It has four teak decks and accommodates 174 passengers, all in outside staterooms.

Delta Queen was locally owned from 1946 to 1985, and Cincinnati — once America’s busiest inland port — was its home. The boat was designated a National Historic Landmark in 1989.

It will spend the winter in New Orleans, as usual, while its owner, Majestic America Line, looks for a buyer. The steamer is tied up next to her younger sister, the Mississippi Queen, which is being dismantled, Clare said.

‘‘For the Delta Queen, this amounts to demolition by neglect,’’ Clare said. ‘‘Mold and mildew are going to set in. This boat needs to be running, carrying overnight passengers to stay alive.’’

Previous endangered lists have included the cottage in Washington, D.C., where Abraham Lincoln drafted the Emancipation Proclamation, Manhattan’s Lower East Side and the wall of architectural masterpieces lining the west side of Chicago’s Michigan Avenue.

The trust began the list in 1988 with the intent of creating a top-10 lineup, but the jury deadlocked at 11 due to an influx of worthy candidates, Brink said.

Winding up on the list would help draw attention to the steamboat’s plight, Brink said.

But Clare believes there is only one way to save the steamboat.

‘‘For the Delta Queen to be kept alive,’’ he said, ‘‘someone has to buy it and use it as it’s meant to be used — carrying passengers on overnight cruises on rivers in the heart of America.’’

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Information from: The Cincinnati Enquirer, http://www.enquirer.com