Complex sentence: The next day six of the crew left, and Nisbet, three days before the Jacatra was posted to sail, and the rest of the crew followed, the captain, mate, second mate, cook, and carpenter being left on board.
Split into simpler sentences: The next day six of the crew left, and Nisbet, three days before the "Jacatra" was posted to sail, and the rest of the crew followed. The captain, mate, second mate, cook, and carpenter were left on board.