Historical clue formulations

• Flat-bottomed riverboat — 2022-02-11
• "Le ___," Matisse work that hung upside down at the Museum of Modern Art for 47 days — 2020-03-15
• French river craft — 2009-08-30
• River craft — 2007-06-09
• Flat-bottomed rowboat — 2003-10-22
• Boat on the Seine — 1994-04-10