Luxury cruising enters computer age.

A century ago, designers drew blueprints with drafting pencils; ship's officers noted their vessel's position with hand-held sextants; and chief engineers listened to their engines for an audible sign that all was running smoothly. Computers have changed things dramatically.

Royal Caribbean Cruise Line's 70,000-ton Legend of the Seas - nearly three football fields long and carrying 1,804 passengers and more than 720 crew members - combines human ingenuity with computer technology The vessel was designed with the aid of computers; its construction schedule was planned by computers; the plasma arc cutters that sliced the steel for its hull were guided by computers; and on the maiden voyage from Miami to Los Angeles on May 16, 1995, its speed, location, safety equipment, engines, navigation, and hotel systems were under the watchful eye of computers.

Virtually every system on board the ship is linked to a computer. Not only does this make a ship's operation easier, safer, and more economical, many systems would be impossible to operate without their use.

In the early planning stages, computer-assisted design was used to create Legend of the Seas' basic design and find a suitable hull shape to minimize drag and maximize fuel economy, yet provide a comfortable ride. Drawings and revisions that normally would have taken a team of draftsmen years to complete were entered into powerful computer systems and altered quickly.

At the shipyard, computers helped determine how much steel should be delivered on specific dates to make certain construction proceeded at a steady pace. The computerized blueprints were fed into computers that control plasma arc cutters to slice steel into precise, large-scale duplicates of tiny drawings. The steel sections then were bent into shape and welded together to form large pieces of the ship, which were lifted by cranes to the drydock where the vessel was assembled. Before the computer age, the construction of an ocean liner could take four or five years. From contract signing to maiden voyage, the creation of Legend of the Seas ran 28 months.

The ship's "That's Entertainment" theater is run by computers as well. its more than 500 kilowatts of lights and sophisticated...