How much gun is needed against a galleon?

What is the smallest World War II gun battery that could destroy a sixteenth-century galleon?

A battery of 40 mm weapons could shred it, but a 4-inch gun would finish the job in fewer shots.

The answer uses a galleon to show how enormous the gap was between wooden sailing warships and later rapid-firing weapons. A battery of 40 mm pom-poms could repeatedly perforate and shred the wooden hull. That does not make it the most efficient weapon for ending the engagement. A 4-inch gun could settle the fight in a few deliberate hits rather than relying on cumulative light-calibre damage.