Leading riverboat operator Croisieurope has named its two vessels slated to enter service in 2009.

The 180-passenger Vivaldi and the 150-passenger Princess Sissi will be sailing the Rhine, Danube, Main and Moselle rivers. Michel Grimm, Croisieurope’s international sales manager, would not reveal any further details, saying only that the vessels “will be similar to our newest ships.”

The addition will boost the company’s fleet to 28 riverboats in 2009, and an annual passenger capacity of more than 200,000. French-based Croisieurope is also planning to add a 150 passenger (yet-to-be-named) ship in 2010, Grimm said.