Warships need counter-drone engagements farther from their sensors

Would 20 mm cannon be suitable for counter-drone defence on vehicles and warships?

They may suit armoured vehicles, but 76 mm is preferred for warships because its range can keep detonations and fragments farther from vulnerable sensors.

A 20 mm cannon is considered a reasonable option for protecting tanks and other armoured vehicles, although that preference is explicitly tentative. Warships present a larger target and benefit from engaging drones at greater distance. A 76 mm weapon offers longer reach and a fragmentation pattern that may catch several drones with a few shells. Destroying a drone very close to a ship can still damage exposed radar and sensor equipment through fragmentation. The preference for 76 mm at sea follows from that need for separation.