The action of 21 April 1806 was a minor engagement between the French and British navies off the Cape Colony during the Napoleonic Wars. The Isle Bonaparte and Isle de France were two French colonies in the Indian Ocean, from which privateers and frigate squadrons could engage in commerce raiding and disrupt British shipping. After encountering a strongly escorted British convoy, the 40-gun Cannonière attempted to flee, but was rejoined by the 74-gun HMS Tremendous. In the ensuing battle, Captain Bourayne displayed superior sailmanship and managed to fend off his much stronger opponent by a combination of manoeuvers that rendered the batteries of Tremendous ineffective, and threatened her with sustaining raking fire. The French frigate thus managed to evade and escape.