NEWPORT, R.I. -- When Bob Tiedemann found the 12-meter yacht Northern Light two years ago, she lay dead on the bottom of Lake Michigan with a dock piling through her belly.

Her varnished wooden deck hatches were gone, the interior was carpeted in waterlogged shag from ceiling to floor, the bottom was soft as grapes and the mast was rotted through.

"She looked," said Tiedemann, "like an old Chevy van."

Northern Light, meticulously built in 1938 of mahogany and cedar planking over oak frames, was the second 12-meter ever drawn by yachting guru Olin Stephens, who went on to design every defender of the America's Cup from 1958 to 1980.

A fitting grave for a thoroughbred? Tiedemann thought not.

So he bought her, had her raised and hauled to Holland, Mich., and that winter he and a small crew of helpers stripped her to the ribs. "We spent that winter putting on a new bottom with the snow swirling around our feet," he said.

By spring, Northern Light was afloat and halfway presentable. Tiedemann sailed her down the St. Lawrence River to the ocean and on to New York for the Statue of Liberty celebration.

There she met up with her old running-mate, Gleam, the 1937 Clinton Crane-designed 12 that Tiedemann had bought and restored in 1975.

It was some reunion. Perhaps the most famous American yachting photograph ever taken is Stanley Rosenfeld's black-and-white shot of Northern Light in hot pursuit of Gleam, spinnakers billowing on a brilliant day off New York nearly a half-century ago. Reunited, the two old 12s bounded along together, pretty as ever.

Now snow-white Gleam and gleaming blue Northern Light lie side by side off the Ida Lewis Yacht Club in Newport Harbor, resurrected by Tiedemann and his yachting obsession.

Almost every day one or both will slip the mooring lines, round the point at Fort Adams and knife past Castle Hill into Rhode Island Sound to sail the ocean.

In the evenings they return, bearing their cargoes of wide-eyed day-charterers. It is a sight, anyone in Newport will tell you, to see the sort of yachts the Vanderbilts once raced sweeping into harbor again under sail.

And no one appreciates it better than Tiedemann, who steers Gleam, the faster of the two, every day she goes out, which is almost every day, every summer.

"They're sensual, graceful- looking boats," he said. "They're long and lean and they have a certain majesty and dignity. I look at them as art -- each one unique, like sculpture."

And what does it take to keep them alive?

"Mostly my own blood, sweat and tears."

Of Northern Light, Tiedemann, 37, says, "They said it couldn't be done. Everyone looked at me like I was nuts. Then, when it was finished, there must have been 200 of them that came by and said, 'You know, I almost bought this boat myself.' "

But they didn't, knowing, as any sensible person would, that a commitment to reconstruct and sustain a sunken, 47-year-old, 67-foot wooden racing yacht would be like buying a sick elephant -- signing your life away.

"It's a never-ending project," agreed Tiedemann. "If I'm not sailing them, I'm working on them."

So why was he smiling? Why would a guy with a list of things to do that never ends wear a perpetual smile?

"Simple," he said, grinning through a cold New England rain as he steered Gleam to her mooring last week. "It's a labor of love."

As a boy in Greenwich, Conn., Tiedemann said, he slipped off evenings to the nearby boat yards. Winters he liked especially, when the great yachts of rich New Yorkers were laid up and he could poke around under their canvas skirts.

When Northern Light turned up in the boat yard 30 years ago it fired a boy's devotion to 12 meters. He would walk around her and think how it would be to own such a boat.

Years later, when he found Gleam languishing, unused and decaying, at a dock on the Morris River off Delaware Bay in 1975, he took the plunge.

He put Gleam right in time for the 1976 bicentennial parade in New York Harbor, then began chartering her in Newport. A few years later he inherited Mariner, his family's 54-foot wooden Alden yawl, which joined the charter fleet.

When word of Northern Light's plight reached him in 1985, the fleet grew to three.

Recently, Tiedemann agreed to buy an antique, 48-foot Huckins powerboat. He said he couldn't help himself. Back in the 1930s, 12-meter owners always had a tender like the Huckins to repair to, so a gentleman could enjoy a drink after racing while the sailing yacht was towed back to port.

"Those were the days," sighed Tiedemann.

So he was born 50 years too late, maybe?

"No," Tiedemann said with that smile. "I was born to do exactly what I'm doing."

As president of the Antique Twelve-Meter Association (P.O. Box 119, Newport, R.I. 02840), Tiedemann is encouraging other boaters to get into the business of salvaging old, wooden 12s.

He said a number -- including Vim, Mitena, Columbia, Anitra, Onawa, Weatherly, Constellation and Nefertiti -- are around and in need of help.

Some day he hopes to hold a big regatta of old 12s off Newport, and make it an annual thing. Rhode Island has "lost the America's Cup," he said, "and may never get it back. But we can still have our own 12-meter fleet right here."

Only trouble is, if you ask him where the needy 12s are, he's reluctant to say. Tiedemann might want those boats for himself.