An escort destroyer was a small warship built to full naval standards which was optimised for air-defence and anti-submarine duties in wartime, but which retained many of the capabilities of a traditional fleet destroyer, enabling it to conduct operations in conjunction with main fleet units as well as carrying out convoy escort and ASW patrols. Typically, escort destroyers had a high enough speed and sufficient armament of guns and torpedoes that they were capable of skirmishing successfully with enemy destroyers and cruisers.