 Two destroyers, ARA "Piedra Buena" and ARA "Hipólito Bouchard" (also ex-USN vessels) were detached from Task Group 79.2 and together with the tanker YPF "Puerto Rosales", joined "General Belgrano" to form Task Group 79.3.By 29 April, the ships were patrolling the Burdwood Bank, south of the islands.On 30 April, "General Belgrano" was detected by the British nuclear-powered hunter-killer submarine .