Connecticut divers have discovered the wreckage of an experimental submarine that was built in 1907 and later scuttled in Long Island Sound.

The Defender, a 92-foot-long boat, was found recently by a team led by Richard Simon, a commercial diver from Connecticut.

Simon said he had been interested in the story of the Defender for years. He spent months going over known sonar and underwater mapping surveys of the bottom of the sound to identify any anomaly that fit the size of the sub.

“A submarine has a very distinct shape,” he said. “It needs to be 100 feet long and 13 feet in diameter. Simon assembled a group of top wreck divers to determine if the Defender was in the location he had identified.

They discovered the Defender lying on the bottom, more than 150 feet beneath the water’s surface, off the coast of Old Saybrook.

“It was legitimately hiding in plain sight,” he said. “It’s on the charts. It’s known about in Long Island Sound, just no one knew what it was.”

Simon described the agony of waiting on the deck of his research vessel, staring at a dive buoy in the fog and waiting for his two divers to surface. Once they did and confirmed they had found a sub, the team erupted in “pure joy,” he said.

Simon said he didn’t want to give the exact depth, because he said that could give away the sub’s location.

The submarine, originally named the Lake, was built by millionaire Simon Lake in hopes of winning a competition for a U.S. Navy contract.

It was an experimental vessel, with wheels to move along the sea bottom and a door that allowed divers to be released underwater, Simon said.

The company lost that competition and Lake then tried refitting the boat for minesweeping, salvage, and rescue work. But he never found a buyer.

But the submarine spent many years unused, docked in New London before eventually being abandoned on a mud flat near Old Saybrook. It was scuttled by the U.S. Army Corps of Engineers in 1946, but the corps never disclosed where, Simon said.

He has contacted the Navy to see if it would be interested in helping preserve the wreckage.