 The British squadron of four frigates sought to blockade the port to prevent its use by the French through the capture of the fortified Île de la Passe at its entrance.This position was seized by a British landing party on 13 August, and when a French squadron under Captain Guy-Victor Duperré approached the bay nine days later the British commander, Captain Samuel Pym, decided to lure them into coastal waters where his superior numbers could be brought to bear against the French ships.Four of the five French ships managed to break past the British blockade, taking shelter in the protected anchorage, which was only accessible through a series of complicated reefs and sandbanks that were impassable without an experienced harbour pilot.