Cadets from the nation's Merchant Marine academies are finding lots of demand and great salaries because of a shortage of licensed mariners. The gangway up to the Empire State VII slopes from the dock at Fort Schuyler in the Bronx, where the East River meets the Long Island Sound. The ship is massive — 530 feet, nine decks - and it's being prepped for its annual summer teaching cruise. To... [5192 chars]