Battle of Grand Port

Battle of Grand Port
Part of the Napoleonic Wars
Combat de Grand Port, Pierre-Julien Gilbert
Date 20–27 August 1810 Location Grand Port, Isle de France 20°23′25″S 57°44′02″E / 20.39028°S 57.73389°E / -20.39028; 57.73389 Result French victory
Belligerents
France	United Kingdom
Commanders and leaders
Guy-Victor Duperré Jacques Hamelin	Samuel Pym
Strength
2 frigates 1 corvette 2 merchant ships. Indirectly involved: 3 frigates 1 brig	4 frigates 1 troopship
Casualties and losses
37 killed 112 wounded 1 merchant ship captured	105 killed 163 wounded 2 frigates destroyed 2 frigates captured 1 troopship captured

The Battle of Grand Port was a naval battle fought on 20–27 August 1810 between squadrons of frigates from the French Navy and the British Royal Navy over possession of the harbour of Grand Port on Île de France (now Mauritius), as part of the Mauritius campaign during the Napoleonic Wars. A 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 forces could ambush them.

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 routes between reefs and sandbanks that were impassable without an experienced harbour pilot. When Pym ordered his frigates to attack the anchored French on 22 and 23 August, his ships became trapped in the narrow channels of the bay: two were irretrievably grounded; a third, outnumbered by the combined French squadron, was defeated; and a fourth was unable to close to within effective gun range. Although the French ships were also badly damaged, the battle was a disaster for the British: one ship was captured after suffering irreparable damage, the grounded ships were set on fire to prevent their capture by French boarding parties, and the remaining vessel was seized as it left the harbour by the main French squadron from Port Napoleon under Commodore Jacques Hamelin.

The British defeat is often considered the worst suffered by the Royal Navy during all of the Napoleonic Wars. It left the Indian Ocean and its vital trade convoys exposed to attack from Hamelin's frigates. In response, British authorities sought to reinforce the squadron on Île Bourbon under Commodore Josias Rowley by ordering all available ships to the region, but this piecemeal reinforcement resulted in a series of desperate actions as individual British ships were attacked by the confident and more powerful French squadron. In December an adequate reinforcement was assembled with the provision of a strong battle squadron under Admiral Albemarle Bertie, which rapidly invaded and captured the Île de France.