Complex sentence: Under the command of Admiral Marriot Arbuthnot, the ships left New York on 26 December and in January 1780, in need of repairs, called in at Savannah, captured by the British the previous month.
Split into simpler sentences: Under the command of Admiral Marriot Arbuthnot, the ships left New York on 26 December. In January 1780, in need of repairs, the forced called in at Savannah, occupied by the British since the previous month.