Historical clue formulations

• Nickname for Oliver Cromwell — 2024-06-11
• Bygone warship — 2010-10-06
• "Old" ship's name — 2005-11-17
• Old ___ (Boston sight) — 2003-04-30
• The Virginia and the Monitor, e.g. — 1998-09-25
• Armor-plated warship — 1997-12-28