 On 21 May, the Arctic Convoy PQ 16 of 35 Merchant ships left Reykjavík in Iceland.It has an ocean escort of six destroyers and four corvettes, with a close covering force of three cruiser and the destroyers "Onslow", "Offa" and "Oribi" joining on 23 May.The cruiser force, including "Onslow" left PQ 16 on 26 May to cover the westbound convoy QP 12.