Complex sentence: The Cuttyhunk lifesavers set to sea to help these men make it to shore, but by the time they reached the area, the two boats had disappeared, one eventually making it to Cuttyhunk, and the other to the Vineyard Sound lightship.
Split into simpler sentences: The Cuttyhunk lifesavers set to sea to help the men make it to shore, but by the time they reached the area, the two boats had disappeared. One boat made it to Cuttyhunk, and the other to the Vineyard Sound lightship.