Complex sentence: By July 1839, he reached Singapore and the following month set his sails to the coast of western Borneo island until Marudu Bay where he find out that piracy had going rampant.
Split into simpler sentences: By July 1839, he reached Singapore and the following month set his sails to the coast of western Borneo island. He continued the sail until Marudu Bay where he find out that piracy had going rampant.