A history of the small, mass-produced warships that defended the Atlantic convoys from U-boats and secured Britain's lifeline to the United States. As the Battle of the Atlantic grew fiercer, Britain and the Commonwealth needed large quantities of new warships to defend their shipping which could be produced cheaply. The two largest type of ship produced were the escort destroyer and the frigate. Escort destroyers were essentially small destroyers optimized for anti-submarine warfare, with speed and anti-surface weaponry sacrificed, while frigates were simpler, designed so they could be built quickly in civilian shipyards. Nearly 200 were built.
