Complex sentence: Newport had successfully raided Puerto Cabellos before in May 1592 where he captured a 200 ton merchantmen, so he knew the area well but they needed supplies badly so headed for Jamaica.
Split into simpler sentences: Newport had successfully raided Puerto Caballos before in May 1592, where he captured a 200 ton merchantmen. He knew the area well but the fleet needed supplies badly so they headed for Jamaica.