A quarter-century ago, the world's first nuclear-powered cruiser, the Long Beach, slid down the ways of the historic shipyard in Quincy, Mass.--and the Ancient Mariner's dream of a ship that would sail the seas forever seemed close to reality.

Yesterday, more than 2,000 people gathered there for another maritime milestone: the christening of the S.S. Energy Independence, an ocean-going coal carrier that could circle the globe five times by burning its cargo.

A 665-foot collier may not excite romantics, but the Energy Independence is the first coal-fired steamship built in this country since 1929.

"Coal-fired plants went out, oh God, just before World War II," said Walter Oates of the U.S. Maritime Administration.

So when the $73 million Energy Independence goes into service later this month hauling 2.4 million tons of coal a year from Norfolk, Baltimore and Philadelphia to power plants along the Massachusetts coast, it will mark the return of a coal-powered steamship to these ports for the first time in decades.

It also will mark a victory at sea for coal in its continuing battle with nuclear energy. Though the U.S. Navy continues to rely on nuclear propulsion systems, particularly for its submarine fleet, the only atomic-powered U.S. merchant ship--the 598-foot Savannah--was mothballed more than a decade ago.

The Savannah, which was subsidized by the government as a research and development project, never turned a profit. But owners of the Energy Independence are hopeful the new coal-powered vessel "will make some money for our investors."

The launching of the Energy Independence also may foreshadow a return of coal-fired steamships to ports around the world in the years ahead. Five others are being built at shipyards in Japan and Italy.

"It makes a lot of sense," said Rolf Glasfeld of General Dynamics' Quincy Shipbuilding Division. "While the trend had been away from steam turbines because they are not as fuel-efficient as a good diesel, coal-fired steam turbines became economical the moment oil hit $15 per barrel."

This new coal-fired vessel was commissioned not by a traditional shipping company but by a utility, the New England Electric System.

Following the 1973 oil embargo, New England Electric, which has more than 1 million customers in Massachusetts, Rhode Island and New Hampshire, began converting some power plants from oil to coal.

"The idea came up in a discussion we were having on how we were going to get coal to our plants," utility Chairman Guy W. Nichols recalled. "I asked, 'If coal is good for a power plant, why wouldn't it be good for a ship?' "

From an economic standpoint, it soon became clear that the idea was "truly a natural," Nichols said.

Because the Energy Independence will burn the same coal that New England Electric is buying in massive quantities for its power plants, Nichols said, the vessel will get its fuel at about half the current cost of an equivalent amount of oil.

"Over the course of a year, our customers probably will see a savings of $2 million on transportation," Nichols said.

Nichols remembers old coal-fired ships as "absolute disasters," with clouds of black smoke belching from the stacks and grime-faced laborers stoking the boiler. The Energy Independence bears little resemblance to the steamships shown in 19th-Century drawings, however.

"When the ship is just getting under way, you will see a plume, but I doubt you will see what you would call a black plume," Nichols said. "We don't anticipate any environmental problems."

As for the 26-man crew, it will "never see any coal in the operation of this vessel," General Dynamics' Leland B. Bishop said.

The coal is enclosed. Two conveyor belts run the length of the vessel and feed coal onto a covered 260-foot-long boom, enabling the Energy Independence to discharge its cargo automatically.

In normal service, the Energy Independence will draw coal from a separate propulsion hold, not from its five cargo holds. "But the vessel will burn the same coal that we carry, so if we need to, we could tap the main cargo," Nichols said.

The ship will carry 36,250 tons of coal and consume 250 tons per round trip. It also will carry a supply of oil as a substitute fuel.