Layered defenses against drone swarms

What can warships use to defend themselves against drone swarms?

They can combine guns and cannon with powerful electronic countermeasures supported by the ship's large electrical capacity.

The answer begins with conventional close-range defenses such as machine guns and cannon. It then emphasizes electronic countermeasures, which may be more effective against control links and navigation than trying to shoot down every small aircraft. Warships have much more electrical generation and physical capacity than most mobile land units, allowing stronger sensors, jammers, and additional equipment. An anecdote about civilian drones being disrupted near naval facilities is offered as circumstantial evidence that electronic protection is already taken seriously. The result is a layered concept: detect and interfere first, while retaining guns for threats that continue toward the ship.