Historical clue formulations

• Floating markers — 2025-12-30
• Harbor markers — 2025-01-09
• Marina markers — 2024-11-05
• Channel guides? — 2024-07-11
• Regatta markers — 2019-11-01
• Lifts — 2014-04-03
• Keeps afloat — 2003-04-15
• They barely keep their heads above water — 2001-09-27
• They may have bells or whistles — 1999-02-05
• Harbor markers — 1998-06-07
• Encourages, with "up" — 1998-01-07
• Raises, as spirits — 1995-09-27