How long can a museum ship remain afloat?

What is the lifespan of a museum ship such as HMS Belfast, and would dry-docking help?

Belfast can last for many years with maintenance, but preserving her requires expensive dry-docking and replacement of deteriorated hull sections.

A floating hull is supported by water but continues to corrode and fatigue, so sections eventually need replacement. Dry-docking can extend its life, although every cycle becomes an expensive specialist project. HMS Warrior demonstrates that an older iron hull can remain afloat when properly cared for. Victory and Cutty Sark illustrate more protective alternatives when continued floating becomes impractical.