Armour without firepower only delays defeat

Who wins between HMS Renown's firepower with little armour and Scharnhorst's armour with no effective guns?

Renown, because armour can postpone damage but a ship without effective weapons cannot stop repeated hits from eventually penetrating or disabling it.

The comparison pits a heavily armed but lightly protected battlecruiser against a well-armoured ship imagined without useful guns. Renown wins because armour can absorb or deflect only a limited sequence of hits. Without offensive power, the protected ship cannot end the engagement before repeated damage defeats it. Warship design must balance protection with the ability to impose damage.