Historical clue formulations

• Ship with three banks of oars — 2020-06-28
• Ancient Greek vessel — 2017-07-09
• Ancient Greek craft — 2016-06-10
• Ancient galley — 2015-01-25
• Persian Wars vessel — 2014-01-01
• Galley of yore — 2006-11-25
• Oar-powered ship — 2004-05-03
• Ancient galley — 1999-11-28
• Old warship — 1997-08-30
• Part of an old Greek fleet — 1997-07-13
• Erstwhile warship — 1997-07-10
• Roman galley — 1996-10-17
• Ancient warship — 1995-02-11