ROCHESTER — 19th-century commercial sailing ship, its twin masts still intact, sits upright in deep, frigid waters off the southern shore of Lake Ontario.

Shipwreck explorers Jim Kennard and Dan Scoville said they located the schooner Milan in summer 2005 about five miles off Point Breeze, 30 miles west of Rochester. They videotaped the 93-foot-long, square-stern vessel this year using an unmanned submersible built with the help of college students.

“It’s not unheard of to have well-preserved ships, but this one is in so good a shape,” Scoville said Monday. “It almost looks like it could be floated” to the surface.

The Milan was hauling 1,000 barrels of salt when it sprung a leak and sank in October 1849. Its crew of nine clambered aboard a yawl and was rescued by a passing ship along with a Newfoundland dog. The animal was carried down with the sinking ship but then popped to the surface and swam to the yawl.

The ship sits evenly on the lake bed, its masts extending 70 feet upward in a dark, almost oxygen-free setting. And while its rigging and sails have long since disintegrated, much else appears largely undamaged.

Both anchors are firmly in place near the bow. The bowsprit — a large, tapered spar extending forward from the bow — is intact, as is the tiller, a large handle for turning the rudder.

“If a ship goes down in a big storm, it usually gets broken up,” Scoville said. “If it goes down on a nice day, it usually breaks when it hits the bottom. This one looks like it just drifted down and set upon the bottom nice and easy.

“At those depths, and the water being so cold, there’s not a lot of oxygen” or light, he added. “It basically helps preserve the wood. If a shipwreck is in shallow, fresh water, the ice will get it or storms will beat it up.”

Built in 1845, the Milan ferried corn, flour, wheat, salt and lumber to ports on lakes Ontario and Erie. It was sailing to Cleveland from Oswego, a port 80 miles east of Rochester, when crew members said they were awakened in the forecastle by splashing water, historical records show.

The inflow was already 18 inches deep when they started pumping out. They removed salt bags from the forward hold and steered south in an effort to get to shore. But the ship ran into southerly winds, made little headway and was abandoned soon before it went under.

While hundreds of ships have been wrecked in Lake Ontario’s harbors and along its shores, fewer than 200 have been lost in the lake, which is 800 foot deep in places, Scoville estimated. About 100 of those wrecks have already been found, many in or near the St. Lawrence Seaway, he said.

The Milan is “the oldest and the prettiest” of at least five wrecks that Scoville and Kennard, both electrical engineers and deep-water divers, have discovered since teaming up five years ago. They undertook months of historical research before announcing their find this month.

“From the Niagara River up to the St. Lawrence, there’s about a dozen that haven’t been found that we think we are capable of finding,” Scoville said.

An obscure newspaper reference to the sinking got the pair started on the Milan’s trail three years ago, and they used sonar equipment to finally locate it.

Because many Ontario shipwrecks lie in water too deep to dive safely, they enlisted a team of seniors at Rochester Institute of Technology last fall to help them build a remote-operated vehicle equipped with cameras to explore the Milan.

Most wrecks and their contents found on the American side of the lake belong to New York.