Pirates armed with grenade launchers and machine guns tried to hijack a luxury cruise liner off the east African coast Saturday, but the ship outran them, officials said. Two boats full of pirates approached the Seabourn Spirit about 100 miles off the Somali coast and opened fire while the heavily armed bandits tried to get onboard, said Bruce Good, spokesman for the Miami-based Seabourn Cruise Line, a subsidiary of Carnival Corp. The ship escaped by shifting to high speed and changing course.