Complex sentence: On 20 September at the taking of Demerara, "Centaur" seized the Batavian 14-gun corvette "Hippomenes", which was acting as a guard ship at Fort Stabroek, Demerara, looking after the Governor's maritime affairs and harbour master for visiting ships.
Split into simpler sentences: On 20 September at the taking of Demerara, "Centaur" seized the Batavian corvette "Hippomenes", which was acting as a guard ship at Fort Stabroek, Demerara. There she looked after the Governor's maritime affairs and served as harbour master for visiting ships.