Complex sentence: When the convoy arrived in Sydney Harbour on 6 August 1806, Bligh assumed the governorship of the colony and retained the "Porpoise" to act as its principal naval unit, ordering Short to return to Britain on in disgrace.
Split into simpler sentences: When the convoy arrived in Sydney Harbour on 6 August 1806, Bligh assumed the governorship of the colony. He retained the "Porpoise" to act as its principal naval unit, ordering Short to return to Britain on in disgrace.