Complex sentence: She returned to home waters for repairs in 1806 and served in the western approaches before joining a fleet under Admiral James Gambier, in 1809, and taking part in the Battle of the Basque Roads.
Split into simpler sentences: She returned to home waters for repairs in 1806 and served in the western approaches. In 1809, "Emerald" was part of the fleet under Admiral James Gambier that fought the Battle of the Basque Roads.