BALTIMORE, SEPT. 11 -- Seagirt Marine Terminal, Baltimore's new $250 million high-technology cargo facility designed to stem the loss of business to Norfolk and elsewhere, received its first ship today.

"A great day . . . an emotional day," Maryland Gov. William Donald Schaefer said at shipside ceremonies.

"A new day dawning," said Rep. Helen Delich Bentley (R-Md.), a longtime port booster.

On the drawing board for 10 years and delayed 18 months in opening, the 265-acre, state-owned ship-truck-rail complex has been promoted by the Maryland Port Administration as a key to reversing the loss of international trade to other ports, especially Virginia's ports in the Norfolk area 150 miles south of Baltimore at the mouth of the Chesapeake Bay.

As dignitaries sipped champagne under a blue and white tent today, a giant high-speed crane nearby unloaded 40-foot steel cargo containers of tractor parts, lumber, wine and computer equipment from the Rafaela S.

The 24,000-ton vessel belongs to the Mediterranean Shipping Co., the first line to sign a lease to use Seagirt.

In the first hour, the crane made 36 loadings and unloadings, called "moves" -- a "hell of a good rate," said Brendan O'Malley, Port Administration executive director.

A conventional crane can do an average of 20 to 22 moves an hour.

Two of the seven cranes at Seagirt have state-of-the-art systems permitting them to handle two containers simultaneously and make up to 55 moves an hour.

The semiautomatic cranes also have computer memories for storing the dimensions of ships so that when the vessels return, they can be handled more quickly.

In a business where time is money, Seagirt has been designed to shorten transactions from crane operations and paperwork to transferring cargo from shipside to nearby rail yards.

Trucks bringing in cargo enter a computerized gate where, without leaving the cab of the truck, the driver gives cargo information over a speaker box, then proceeds to shipside. There, a crane lifts the container from the truck bed and places it in a predesignated spot on the ship.

Small, specially designed trucks also move containers between shipside and railroad tracks a few hundred yards away within the terminal. Before the railroad tracks were brought in, truckers had to haul containers several miles to Conrail and CSX railheads elsewhere in the city.

"The faster the box {container} moves, the more the costs are kept down," said Port Administration spokeswoman Sara Moriarty.

With reduced costs, Baltimore hopes to win back some of the tonnage it has lost to other ports in the last seven years. Several shipping lines have pulled out of Baltimore, citing discount rates and cheaper labor elsewhere.

Officials have said they expect cargo at the port to drop another 4.4 percent this year to an annual total of 6.6 million tons. But they say it should start to level off in 1991 and even increase in 1992, especially if Seagirt catches on.

So far, two shipping lines have signed Seagirt leases, Mediterranean, headquartered in Geneva, and Evergreen Marine Corp., of Taiwan, the largest container shipping company in the world. In both cases, the lines already did business in Baltimore but agreed to move their operations from older facilities, such as Dundalk Marine Terminal, to Seagirt.

Schaefer, after wooing both lines, flew to Geneva and Taiwan this summer to attend lease-signing ceremonies. Mediterranean agreed to a six-year lease with ships arriving at Seagirt weekly and moving 17,000 to 20,000 containers annually. Evergreen signed a three-year lease. Its first ship is due at Seagirt in October.

Port officials are negotiating additional leases with other lines.