An international voyage in the course of which a ship is not more than 200 miles from a port or place where the passengers and crew could be placed safely. Neither the distance between the last port of call in the country in which the voyage begins and the final port of destination nor the return voyage shall exceed 600 miles. The final port of destination is the last port of call in the scheduled voyage at which the ship commences its return voyage to the country in which the voyage began, (SOLAS, Chapter III).