On 20 September 1780, Reynolds assumed command of HMS "Monarch", a ship of the line bearing 74 guns and sailed with Rear-Admiral Sir Samuel Hood's reinforcements headed for the West Indies in late October. He was present at the Capture of Saint Eustatius on 3 February 1781, and was chosen by Admiral George Rodney to depart with the "Monarch", HMS "Panther" and the HMS "Sybil", and pursue the Dutch frigate "Mars". On 4 February Reynolds engaged "Mars", forcing her to strike her colors and surrender. During the action the senior officer, Rear-Admiral Willem Krull, was killed. On 29 April, serving under Admiral Hood, Reynolds, still in command of "Monarch", was present at the Battle of Fort Royal.