OFF THE KEWEENAW PENINSULA, MICH - It was a perfect day for shipwreck hunting.

Lake Superior was placid, and summer sunshine warmed Kraig Smith's tanned, stubbled face as he pitched the torpedo-shaped "tow-fish" over the side of his 22-foot C-Dory and watched the cord play out into the wake.

Smith's friend Jerry Eliason was at the helm of the boat. He kept a precise course with a GPS unit, while monitoring a laptop screen receiving signals from the tow-fish -- a pet name for their homemade sidescan sonar transducer.

Somewhere down below, hidden in 500 feet of water, lay the wreckage of the Sunbeam, a wooden sidewheeler that sank with at least 25 passengers in 1863.

Eliason, Smith and two friends are determined to find it. They are a rare breed.

They are adventurers who spend much of their spare time and money searching for the shipwrecks that litter the bottom of Lake Superior.

"There are only about 50 serious wreck hunters on the whole Great Lakes, and those guys on western Lake Superior are in the top five," said Brendon Baillod, a maritime historian who runs www. ship-wrecks.net, a Great Lakes shipwreck research website.

About 100 Lake Superior shipwrecks remain unaccounted for, while the locations of more than 200 other submerged wrecks are known.

Eliason, Smith, and their friends Ken Merryman and Randy Beebe already have discovered eight of the lake's long-lost wrecks. Sometimes, the hunt entails hundreds of hours on the water, going back and forth with sonar -- "mowing the lawn," they call it.

They don't hunt wrecks for treasure; there's very little on the Great Lakes. Rather, they say they do it to have fun, solve mysteries and preserve the wrecks they find, working in the off-season to get their finds declared historic sites.

"They're hobbyists who all have day jobs, but they're very serious," Baillod said. "They don't steal from wrecks or make them private playgrounds. They protect them to add to cultural and maritime history."

Search began with diving

Eliason, who lives just outside Duluth in Scanlon, said their passion for finding wrecks grew out of their love for scuba diving in the 1970s.

"As a kid I was mesmerized watching 'Sea Hunt' with Lloyd Bridges on TV," he said.

They dived down to known wrecks, then began looking for lost ones in the shallower water to which they were limited by the pre-GPS and LORAN technologies of the time.

"Even if you could find a deepwater wreck, you couldn't get back to it a second time," Eliason said.

So they stuck to shorelines and reefs, often donning scuba gear and riding underwater "tow boards" tied to a trolling boat. That's how they found the propeller from a 1906 wreck, the Theano, near Thunder Bay, Ontario, in 1981. They had to wait until 2005, and better technology, to locate the rest of the Theano in 300 feet of water.

In 1988, Eliason and Smith, of Rice Lake, Wis., made news by using a $149 fish-finder to locate their first deepwater wreck, the Onoko, a historic iron-hulled prototype for the modern Great Lakes freighter. It sank near Knife River on the North Shore in 1915 in more than 200 feet of water.

Eliason said they had searched for the vessel more than 500 hours in his open Zodiac inflatable boat. Such relentlessness has been a key to their success. Eliason said they once went 13 years without a discovery.

A near-death experience

A year after finding the Onoko, Eliason made a mistake that changed his life forever.

On a 170-foot dive to the John B. Cowl off Whitefish Point on the Upper Peninsula, he let one of his air tanks go empty before attempting to switch to the other. But he'd left the second mouthpiece dangling behind him and couldn't find it in time.

"I had to choose between drowning and getting the bends," he said, referring to the sometimes fatal decompression sickness that strikes divers who ascend too quickly. His prescribed ascent time on that dive was 90 minutes. He shot to the surface in less than 60 seconds.

Decompressing that fast caused the dissolved nitrogen in his bloodstream to fizz. Gas pockets formed, expanding and blocking blood vessels, killing nerves and tissue.

Eliason's life was saved, thanks to his companions who quickly got him on a helicopter to a Milwaukee hospital. After a five-week stay, he slowly regained the ability to walk.

His right leg and left arm were permanently damaged -- ending his diving days. But his desire to hunt wrecks didn't sour, especially as technology began to put sidescan sonar and drop-down cameras within reach of the average guy.

That winter of 1989, Eliason traveled to Ottawa to read the Canadian government's report on the 1942 sinking of the Judge Hart, a wreck that had eluded searchers. Successful wreck hunting always begins in archives and libraries, he said.

After concluding that the report contained a transcription error, Eliason and Smith calculated a probable location and found the Hart the next spring, once again using a fish-finder.

New technology helps

Added expertise and new equipment and technology made the western Lake Superior hunters more productive.

Eliason and his son, Jarrod, built the group's first sidescan sonar system, enabling them to cover an 1,800-foot-wide swath of the lake bottom on a single pass, compared to the 100-foot scope of a fish-finder. To test the system in winter, they walled off a section of Eliason's basement and filled it will 2,900 gallons of water.

They hooked up with Merryman, an electrical engineer from Fridley and accomplished deepwater diver who guides divers to wrecks off Isle Royale National Park. Randy Beebe, an airline pilot from Duluth, joined the group, bringing expertise in diving and in obtaining permits from government agencies.

All their advances came together in 2004 -- a banner year in which the intrepid hunters made Great Lakes history with three major discoveries:

• They found the fishing boat Thomas Friant, lost since 1924, 13 miles off Two Harbors, Minn.

• A month later, off Michigan Island in the Apostles, they came across the graceful three-masted schooner Moonlight, which sank in 1903 off the Wisconsin shore.

• And on Halloween 2004, the hunters were off Two Harbors when something amazing happened. For the third time that year, what clearly appeared to be a shipwreck appeared on the screen of the laptop computer.

Bingo! The Holy Grail

When they lowered a camera, thinking they'd found the sought-after wooden-hulled Wallace, they were surprised to find a steel hull instead.

It hit them like lightning: in western Lake Superior, the only missing steel vessel was the Benjamin Noble, which sank in a 1914 storm.

The Noble, having vanished with all 20 of its crewmen and leaving only sketchy information on its probable location, was considered the Holy Grail.

"We felt giddy," Eliason said, "like when you're a kid."

Scanning the screen for signs of the Sunbeam one day recently, Eliason declared, "It must be noon somewhere." He cracked open a beer and rested it in the crook of his damaged arm.

He said that he used to envision that they would find the Robert Wallace, and then he might retire from shipwreck hunting. As it was, somebody else found the Wallace, making it the one that got away, "our unrequited love."

Now, he said, "it's the Sunbeam." There might always be another one, he admitted, adding that he'll search for wrecks only as long as his friends are there to share the moments.

"It's the team-effort," he said, "that makes this fun."

Larry Oakes • 612-269-0504