Escort carriers made Atlantic convoys harder to shadow and attack

How were escort carriers used in the Battle of the Atlantic?

They used fighters to drive off reconnaissance bombers and, more importantly, Swordfish with ASV radar to hunt U-boats around convoys.

Escort carriers provided limited fighter cover, especially against aircraft such as Condors that could report convoy positions. Their larger value came from Swordfish anti-submarine patrols. Slow, quiet, and persistent Swordfish became dangerous once fitted with ASV radar and depth charges. They could catch a U-boat looking for convoy targets and bring destroyers down on it.