SAN DIEGO - The Coast Guard medically evacuated the master of a 1,092-foot tanker approximately 40 miles west of Escondido, Aug. 11, 2013. The chief mate of the Genmar Zeus, a Marshall Island-flagged oil tanker, contacted the Coast Guard on VHF-FM channel 16, requesting assistance for the master who was suffering from constant and severe stomach pain and vomiting. U.S. Coast Guard video.