ROCHESTER, N.Y.— After more than 160 years, the twin masts of the Milan still stand erect — all the more remarkable because the commercial sailing ship sits in the dark depths of Lake Ontario.

“It almost looks like it could be floated” to the surface, shipwreck explorer Dan Scoville said on Monday.

Mr. Scoville and fellow explorer Jim Kennard located the schooner in the summer of 2005 off the southern shore of the lake. They videotaped the 93-foot-long, square-stern vessel this year using an unmanned submersible built with the help of college students.

The ship sits upright on the lake bed at a depth of more than 200 feet. Its masts extend 70 feet upward in the dark waters.

“At those depths, and the water being so cold, there’s not a lot of oxygen,” Mr. Scoville said. “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.”

While its rigging and sails have long since disintegrated, much of the 1845 ship 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,” Mr. 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.”

The Milan sprung a leak and sank in October 1849 while transporting 1,000 barrels of salt from Oswego, a port 80 miles east of Rochester, to Cleveland.

Crewmembers recalled being awakened in the forecastle by splashing water, historical records show. The water had risen to 18 inches before they started pumping it 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.

Its crew of nine and the ship’s Newfoundland dog clambered aboard a yawl and were rescued by a passing ship.

Messrs. Scoville and Kennard began their hunt for the Milan three years ago after spotting an obscure newspaper reference to the sinking. They located the wreckage with the help of sonar equipment.

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.

The Milan is “the oldest and the prettiest” of at least five wrecks that Messrs. Scoville and Kennard, both electrical engineers and deep-water divers, have discovered since teaming up five years ago. They undertook months of 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,” Mr. Scoville said.