Do fundo do mar... Sea bottom
Tuesday, March 08, 2005
Frigid lake waters preserve piece of history
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Boston.com News
By Wilson Ring
February 27, 2005
FERRISBURGH, Vt. -- A bridge built across Lake Champlain by about 2,500 underfed and sick Continental Army soldiers in the late winter and early spring of 1777 was considered a marvel of 18th-century engineering.
Historians figure thousands of huge pine logs were skidded onto the ice in March and April, notched together like Lincoln Logs, and then sunk with rocks through holes the soldiers cut in the ice.
By spring 22 caissons, some up to 50 feet tall, reached the surface of the lake where they were joined by a deck that allowed people to walk between Fort Ticonderoga in New York and Mount Independence in Orwell.
Now a piece of one of those caissons sits in the preservation laboratory at the Lake Champlain Maritime Museum being made ready to give museum visitors a glimpse of the 228-year-old bridge.
''When you look at what they wanted to do, it connects you right to the American Revolution," said Maritime Museum Executive Director Art Cohn.
About 2,500 American troops used the 16-foot-wide bridge built on top of the caissons to flee the British Army that was bearing down on Fort Ticonderoga in July 1777.
The British occupied the fort and later destroyed the bridge. But many of those same colonial troops who fled Ticonderoga played a role in defeating the British in the Battle of Saratoga, one of the pivotal battles of the Revolutionary War, three months later.
The caissons the bridge rested on remain under water. They are all deep enough so they don't interfere with boats on the lake, Cohn said.
The 26-foot beam is estimated to weigh between 1,500 and 1,800 pounds. It washed ashore last year near Fort Ticonderoga on the New York shore of Lake Champlain.
The beam was trucked to the Maritime Museum in December where it is being dried out and made ready for public display.
The size and condition of the beam mean it isn't as difficult to preserve as some other wooden artifacts pulled from Lake Champlain.
The original tree that was cut nearby in Vermont or New York is believed to be dense, white pine. Eighteenth-century forests were full of such trees.
''It's certainly old growth," said Chris Sabic, the museum's director of conservation.
The cold lake water helped preserve the timber.
''The wood was never completely waterlogged," Sabic said.
''The conservation is going to be very passive," he said. ''We're not trying to impregnate it with chemicals. We are really just letting it dry out as slowly as possible in a controlled environment."
That control comes from simply wrapping a plastic tarp around the beam for part of the day.
The simple conservation technique is a marked contrast from some other wooden Lake Champlain artifacts that have required months or years of expensive preservation.
For example, it took years to preserve an anchor from a British warship from the War of 1812 that was pulled from the lake near Plattsburgh, N.Y.
In that case the anchor was dried by soaking it in alcohol. Then the anchor was soaked in a solution that contained pine rosin.
The entire process took several years. The anchor is now on display at the Plattsburgh City Hall.
Cohn said divers discovered the bridge caissons in 1983. They were still largely intact, laid out in an arc between the two shores.
The discovery came before the museum opened. So Cohn and the other divers moved on to other projects.
Cohn and the others returned to the bridge in 1992.
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Boston.com News
By Wilson Ring
February 27, 2005
FERRISBURGH, Vt. -- A bridge built across Lake Champlain by about 2,500 underfed and sick Continental Army soldiers in the late winter and early spring of 1777 was considered a marvel of 18th-century engineering.
Historians figure thousands of huge pine logs were skidded onto the ice in March and April, notched together like Lincoln Logs, and then sunk with rocks through holes the soldiers cut in the ice.
By spring 22 caissons, some up to 50 feet tall, reached the surface of the lake where they were joined by a deck that allowed people to walk between Fort Ticonderoga in New York and Mount Independence in Orwell.
Now a piece of one of those caissons sits in the preservation laboratory at the Lake Champlain Maritime Museum being made ready to give museum visitors a glimpse of the 228-year-old bridge.
''When you look at what they wanted to do, it connects you right to the American Revolution," said Maritime Museum Executive Director Art Cohn.
About 2,500 American troops used the 16-foot-wide bridge built on top of the caissons to flee the British Army that was bearing down on Fort Ticonderoga in July 1777.
The British occupied the fort and later destroyed the bridge. But many of those same colonial troops who fled Ticonderoga played a role in defeating the British in the Battle of Saratoga, one of the pivotal battles of the Revolutionary War, three months later.
The caissons the bridge rested on remain under water. They are all deep enough so they don't interfere with boats on the lake, Cohn said.
The 26-foot beam is estimated to weigh between 1,500 and 1,800 pounds. It washed ashore last year near Fort Ticonderoga on the New York shore of Lake Champlain.
The beam was trucked to the Maritime Museum in December where it is being dried out and made ready for public display.
The size and condition of the beam mean it isn't as difficult to preserve as some other wooden artifacts pulled from Lake Champlain.
The original tree that was cut nearby in Vermont or New York is believed to be dense, white pine. Eighteenth-century forests were full of such trees.
''It's certainly old growth," said Chris Sabic, the museum's director of conservation.
The cold lake water helped preserve the timber.
''The wood was never completely waterlogged," Sabic said.
''The conservation is going to be very passive," he said. ''We're not trying to impregnate it with chemicals. We are really just letting it dry out as slowly as possible in a controlled environment."
That control comes from simply wrapping a plastic tarp around the beam for part of the day.
The simple conservation technique is a marked contrast from some other wooden Lake Champlain artifacts that have required months or years of expensive preservation.
For example, it took years to preserve an anchor from a British warship from the War of 1812 that was pulled from the lake near Plattsburgh, N.Y.
In that case the anchor was dried by soaking it in alcohol. Then the anchor was soaked in a solution that contained pine rosin.
The entire process took several years. The anchor is now on display at the Plattsburgh City Hall.
Cohn said divers discovered the bridge caissons in 1983. They were still largely intact, laid out in an arc between the two shores.
The discovery came before the museum opened. So Cohn and the other divers moved on to other projects.
Cohn and the others returned to the bridge in 1992.
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