Move over, Lake Minnetonka.

The largest lake in the Twin Cities metro area isn't the only one with shipwrecks strewn across its depths.

A pair of archaeologists have found the remains of several sunken vessels on the bottoms of White Bear Lake in Ramsey County and Lake Waconia in Carver County.

Ann Merriman and her husband, Chris Olson, reported the findings recently of surveys they took last August.

They used high-quality sonar equipment to scan the bottom of lakes and rivers methodically, searching for possible archaeological sites.

In White Bear Lake, they found three new shipwrecks "for sure," said Merriman, along with three probable and 14 possible wrecks. In Lake Waconia, Merriman and Olson found 10 probable wrecks and 22 possible wrecks.

The couple founded the nonprofit Maritime Heritage Minnesota in 2005, and studied all of Minnetonka's lake bottoms in 2011 and 2012.

Most of the findings are valuable as history rather than sunken treasure, since the steamboats, barges, sailboats and other objects they've identified were usually stripped of anything valuable and intentionally sunk when they became damaged or obsolete.

1880s tourism was different

"They're reminding us that there is a history underneath those lakes, and that history is related to times quite different than today as far as recreation and industry," said Scott Anfinson, Minnesota state archaeologist, referring to the researchers.

Like Minnetonka, White Bear Lake and Waconia have a long history of boating, including ferries and steamboats that carried tourists to lakefront hotels and amusements in the late 19th and early 20th centuries. "If you look at a picture of Excelsior or Wayzata from 1880, you'd think you're looking at St. Louis," Anfinson said. "You'll see 10 big steamboats docked, some of them large enough to carry 1,000 passengers."

Early boat traffic brought supplies to the pioneers who settled on White Bear Lake, Waconia and Minnetonka before there were many roads and bridges, Anfinson said. They also brought tourists from Minneapolis and St. Paul who took the railroad or trolley lines to the lakes and continued by ferries, steamers and smaller launches.

"Resorts popped up all around those lakes," said Anfinson, and so did hotels and amusement parks: Big Island at Minnetonka, Wildwood Park at White Bear Lake and Coney Island at Waconia.

One of the smaller steamboats of that period -- painted the same color as streetcars -- was the Minnehaha, built in 1906. It was scuttled in Lake Minnetonka in 1926, but raised in 1980 and restored by volunteers a decade later. It now cruises the lake on summer and fall weekends and holidays, operated by the Museum of Lake Minnetonka.

Steamboat remains

Merriman said that in White Bear Lake, one set of sonar images shows a wreck about 25 feet long that lies in 28 feet of water. The images are not detailed enough to determine the type of wreck or its definite size without diving to inspect it closely, she said.

Another image could be the remains of one of the large steamboats or barges that plied White Bear Lake around 1900. A third lies in the deepest section of the lake, but its shape and approximate size -- 56 feet -- make it a likely steamboat.

The steamer White Bear reportedly burned and was towed into deep water and sunk, according to a local person who is now deceased, Merriman said.

In Lake Waconia, many of the possible wrecks are near Coney Island, where cottages, boathouses and a hotel in 1886 attracted tourists. The island and hotels in the city of Waconia offered band concerts, dance halls and boat excursions in the late 1800s.

Anfinson said that Merriman and Olson are the only underwater archaeologists in the state.

"There are quite a few in Michigan and Wisconsin because they're still researching the Great Lakes," he said. "But in Minnesota, we're sort of unique because we're looking inward at our inland water and its history."

Merriman said Maritime Heritage has received several $7,000 grants from the Arts and Cultural Heritage Fund -- part of the Clean Water, Land and Legacy Amendment -- to conduct lake and river surveys. It will also use funds to take the next step: underwater diving to determine whether the sonar images are pieces of history or something else, such as sunken fish houses and docks, piles of rocks or waterlogged trees.

Occasional surprises

Even items that turn out not to be shipwrecks can be interesting, Merriman said.

Volunteer divers working with her last fall checked out one of the images detected in Lake Minnetonka near Wayzata.

"We had gone over it with our sonar and we assumed it was going to be a small boat," Merriman said. "It turned out to be a car."

A 1955 Mercury Monterey four-door sedan, to be exact. Perhaps it fell through thin ice while someone was fishing, she said, or perhaps it was abandoned to get rid of it.

"It's got some zebra mussels on it so it's getting deteriorated by that," Merriman said. "But it's still got glass in the back window, headlamps, a steering wheel, and a lot of local divers have been diving on it."

Anfinson said that anything abandoned at the bottom of lakes legally belongs to the state Department of Natural Resources. Objects known to have sunk more than 50 years ago are overseen by his archaeology office, and are sometimes designated officially as nautical archaeology sites.

Divers are welcome to explore these sites and in some cases have been doing so for years, Anfinson said, but no one is allowed to disturb, damage or take property that does not belong to them.

Merriman said she hopes to conduct more dives next spring to check the most promising sonar images in the three lakes.

Enough wrecks have already been documented on Lake Minnetonka, she said, that it may become a national historic shipwreck district.

"It's a rarity that 10 different types of vessels are preserved on the bottom of the lake," she said. "It's a unique opportunity to preserve such a big part of Minnesota's maritime history."

Tom Meersman • 612-673-7388