American waterways are about to get a few more cruisers.

With demand increasing for Mississippi River sailings, American Queen Steamboat Company said Tuesday it is adding a third vessel to its fleet next spring.

The Memphis-based company said it had purchased an American-made hull — which was most recently a gaming boat in Iowa — and would gut and entirely remake the vessel as the 166-passenger American Duchess.

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Ted Sykes, president and chief operating officer at American Queen Steamboat Company, said the operator’s two ships are running full most of the time this year, and bookings for 2017 are running at double the rate they were a year earlier.

“We’re turning people away, so we have to get more capacity,” he said.

The privately held company did not disclose how much the vessel and its rehab would cost. The all-suite riverboat will include two restaurants.

American Duchess will sail the Mississippi River and tributaries and will stay at destinations including Nashville and New Orleans overnight, a new option for the line. Because it is 100 feet shorter than American Queen, which also sails the Mississippi, it will be able to visit some additional locations including Ottawa, Ill. outside of Chicago.

The operator’s other ship, American Empress, sails in the Pacific Northwest.

Sykes said interest in U.S. river cruising has been growing as awareness increases and early customers return for new experiences.

While river cruise companies have been adding ships at a furious pace in recent years, most of those offerings are in Europe. The U.S. river cruise segment is still in its early days, with Memphis-based American Queen Steamboat Company and American Cruise Lines as the main players.

“Now we have a well-developed U.S. product, so the veteran European river cruisers are saying ‘Let’s stay closer to home,'” Sykes said.

He said there is plenty of room for the niche product to grow: Of 700,000 Americans who take a river cruise each year, Sykes said, between 50,000 and 60,000 do so in the United States.

“There’s a huge base of cruisers that we’re serving a very tiny fraction of,” he said.

Photo Credit: The American Queen is shown in this promotional image. Owner American Queen Steamboat Company is adding another boat to sail the Mississippi River next year. American Queen Steamboat Company