CAPE VINCENT — There might be more sunken cannons in the depths of the St. Lawrence River near Carleton Island's Fort Haldim, according to a group of archaeologists and scuba divers.
The initial survey of a small area off the island this summer conducted by the group showed no evidence of large iron objects. However, the group hopes to expand the search once it gathers more historical evidence that there are, in fact, more cannons disposed of by the British in the early 1800s.
Dennis R. McCarthy, co-founder of the St. Lawrence Historical Foundation, a nonprofit organization based in Cape Vincent that conducted the survey, said the search began after two scuba divers claimed in 2008 that they saw a sunken cannon off of Carleton Island several years ago.
"Our aim was to go out there, do a survey, locate the cannon and measure it," said Mr. McCarthy, a certified scuba diver and resident of Cape Vincent.
According to the scuba divers, he said, the cannon was buried under "two feet of mud, resting close to vertical," and a diver could "put his fist into the muzzle's opening."
The historical foundation was granted a state permit to excavate archaeological materials on state lands in May.
Based on the location provided by the scuba diver, a small team of six volunteers — Mr. McCarthy and his wife, Kathryn C.; Bob Seiselmyer, a diver from Syracuse; Douglas J. Pippin, an archaeologist and professor at SUNY Oswego; Raymond I. "Skip" Couch, a veteran diver from Clayton, and James W. Kennard, a shipwreck explorer from Rochester — conducted a survey of the bottom of the river from June to September.
The crew conducted a visual survey and used a high-resolution side scan sonar to map the bottom of the river and a magnetometer to identify large iron objects such a cannon.
"We had a pretty state-of-the-art equipment," Mr. McCarthy said.
He said historical records indicate about five cannons were thrown into the river about 1807 by the British military.
So far, three iron cannons have been recovered by scuba divers — two in the 1960s and the third in 1973.
Mr. McCarthy said these cannons have great historical significance as they are some of the oldest artifacts found in the upper St. Lawrence River and the Great Lakes.
The older cannons already were more than 150 years old when they were thrown into the river, some 200 years ago, he said.
Mr. McCarthy said additional cannons could be buried anywhere near Carleton Island and that it would be impossible for a small group to search such a large area without any leads.
He said the group will further analyze the side scan images of the general area around the target site this winter and search historical records for the exact number of cannons sunk in 1807 before it conducts another survey.