In the summer of 2007, Mark Munro of Griswold and a group of fellow wreck divers discovered a 70-foot intact shipwreck in Fishers Island Sound.

While its wooden timbers had rotted, they found a diesel engine, ship's wheel and two bells and personal items such as a pocket watch, pewter mirror and tea cups.

Despite five years of historical research and reaching out to local historical groups and experts, the identity of the ship is still a mystery to Munro, who believes it sank in the Hurricane of 1938.

He is now asking the public for help, thinking someone may have heard about the wreck or knows something about the ship, which is thought to have been involved in the menhaden fishery or been converted to a yacht.

"We've had a lot of leads, but none of them have panned out," he said Monday. "It's interesting because it's right in the middle of Fishers Island Sound where there's always been lot of traffic, but no one knows about it."

He said the wreck, which is in the deepest part of the sound at 75 feet, had a forward bridge with a searchlight, an open section in the middle which led to the fish hold and a rear structure that housed the crew quarters. That's where artifacts such as plates, cups and a watch were found, as well as portholes.

Munro's road to discovering the wreck began in 2005 when he began scouring a 1995 government sonar survey of Long Island Sound for possible wreck sites.

Then in 2007, using his own high-resolution side scan sonar system, he and his fellow explorers from locally based Baccala Wreck Divers found three wrecks in Fishers Island Sound and dove on them. One was a part of a barge, the second a scuttled 40-foot houseboat. Neither interested the wreck hunters.

The third target, which was covered in silt, is the wreck Munro is now trying to identify. Because it was the third and most interesting one the group explored, the divers now refer to it as "Three's a Charm."

Munro has so far been unable to track the equipment and artifacts on the wreck back to a specific boat, in some cases because the manufacturers are no longer in business.

The diesel batteries have provided one clue, having been made prior to 1936. That's why Munro believes the ship may have been claimed by the 1938 Hurricane.

While it seems unusual there are no records of the ship's demise, Munro said it may have just been transiting the area. In addition, thousands of ships were lost in the hurricane.

"We're just trying to find out where it came from and how it got to this place," he said. "We hope someone might have some local knowledge about it."

Munro said he and his fellow divers don't just like to find and explore new wrecks each summer, they also enjoy solving the mysteries behind what they find and researching their history.

In 2009, they found the 249-foot-long wooden coasting schooner Jennie R. Dubois, which was built in West Mystic and was the largest coasting schooner built outside of Maine. They discovered the ship, which sank in 1903, 6 miles southeast of Block Island in 100 feet of water.

Last summer, he said his group found nine new wrecks between Watch Hill and Point Judith, R.I., most of which were old coal barges. He said they also continue to search for the remains of U-550, a World War II German U-boat sunk off Nantucket.

More information about Munro and his group can be found at www.soundunderwatersurvey.com.

j.wojtas@theday.com