Coastal Command's wartime anti-submarine combination

What was Coastal Command's best anti-submarine warfare weapon?

Its most effective wartime method combined airborne radar and the Leigh Light with depth charges, rather than relying on one weapon alone.

Airborne radar, the Leigh Light, and depth charges formed the deadly wartime combination. Radar found a surfaced submarine at night, the light enabled the final approach, and depth charges delivered the attack. Short Sunderlands could also damage submarines with machine-gun fire, but the larger lesson is that sensors and weapons worked together.