In June 1941, within weeks of the German invasion of the USSR, the first British aid convoy set off along the dangerous Arctic sea route to Murmansk, arriving in September. It carried 40 Hawker Hurricanes along with 550 mechanics and pilots of No. 151 Wing in Operation Benedict, to provide air defence of the port and to train Soviet pilots. The convoy was the first of many convoys to Murmansk and Archangelsk in what became known as the Arctic convoys, the returning ships carried the gold that the USSR was using to pay the US.