Johnstone sailed on his expedition from Spithead on 13 March 1781 in command of 46 ships, including five ships of the line (the 74-gun , the 64-gun , and the 50-gun ,  and ), four frigates (the 38-gun HMS Apollo, the 36-gun ,  and the 28-gun ), the fireship  and the bomb vessel . He also had seven light armed cruisers, two cutters and a sloop to serve as despatch vessels, four transports, eight storeships, and thirteen Indiamen.
Johnstone embarked on his expedition from Spithead on 13 March 1781, commanding 46 ships, including five warships (the 74-gun , the 64-gun , and the 50-gun ,  and ), four frigates (the 38-gun HMS Apollo, the 36-gun ,  and the 28-gun ), the fireship  and the bomb vessel . He also had seven light armed cruisers, two cutters and a sloop to serve as despatch vessels, four transports, eight storeships, and thirteen Indiamen.