By CURT ANDERSON A Hialeah man has been convicted in the 2007 hijacking of the "Joe Cool" charter boat and slayings of four people aboard.The verdict on 16 counts against 21-year-old Guillermo Zarabozo was returned Thursday by a Miami jury after less than two days of deliberations. The former security guard's first trial ended in a hung jury on most charges.Prosecutors said Zarabozo plotted with 37-year-old Kirby Archer to hijack the boat to Cuba and kill its captain, his wife and two crew members.