A 75-Ton Chain Once Stretched Across the Hudson to Stop the British

More than 200 years after the chain’s construction, we shed light on its role in the Revolutionary War.

More than 200 years after the Great Chain’s construction, we shed light on its role in the Revolutionary War and the Hudson Valley.

From the earliest moments of the War for Independence, each side knew that the key to victory was the Hudson River. The hotbed of the revolution was in Boston and most of Gen. George Washington’s nascent Continental Army were from the northeast. The river separated the northeast from the rest of the country. If the British took control of the river, the head would be cut off from the body, and both sides knew what would follow.

By 1776, the British had seized New York City and held on to Canada, and had a water route just about the entire way between the two. Blocking British ships became paramount. But American fortifications in the valley were not sufficient. Gen. George Washington needed a great idea. He got it from an English-born patriot named Thomas Machin.

Machin knew water. He had been an apprentice canal builder in England, and, as a captain in an artillery company he was called by Washington to help defend the river at the Hudson Highlands. The river was narrow there, and since ancient times armies had placed sharpened logs, scuttled ships, and other debris in a narrows to block passage. But here the river was too deep. Machin had his a-ha moment: Why not forge an iron chain and float it across the river, anchoring it at either shore?

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The Great Chain floated on sharpened log rafts across the Hudson River at West Point.
The rafts allowed the chain to be removed during the winter. Remnants of the rafts remain on Constitution Island.

Some kind of chain or boom system had been in the original concept to block the Hudson as part of a fortification system, says Col. James M. Johnson (retired) of Marist College, where he is the Frank T. Bumpus Chair in Hudson River Valley History, military historian of the Hudson River Valley, and executive director of the Hudson River Valley Institute.

Related: 6 Things to Know About George Washington’s Hudson Valley History

“Gen. James Clinton and Christopher Tappen [the brother of Clinton’s wife] recommended [using] them in their report of June 1775. They also mentioned the possibility of using ‘four or five booms chained together on one side of the river, ready to be drawn across,’ as a means of blocking navigation,” he says.

Remnants of the chain are preserved and displayed throughout New York State, including at Washington’s Headquarters State Historic Site in Newburgh, Boscobel House and Gardens, the NYS Museum, and the U.S. Military Academy at West Point | Photo by Doc Bayne

Their report recommended West Point, “as it is not only the narrowest part of the said river, but best situated, on account of the high hills contiguous to it, as well on the west as east side of the river which cover those parts; so that without a strong easterly wind, or the tide, no vessel can pass it; and the tide on said part of the river is generally so reverse, that a vessel is usually thrown on one side of the river or the other, by means whereof such vessel lay fair and exposed” to the men and guns lying in wait on shore.

They tried a chain at Fort Montgomery first, in 1777. When British Gen. Henry Clinton sailed upriver to support Gen. John Burgoyne at Saratoga, in the fall of 1777, the chain stopped him — sort of. Clinton recognized the chain was too much of an obstacle, but the troops on shore were not. Clinton’s men disembarked, overpowered the American guards, removed the chain and sailed upriver, burning Kingston for good measure.

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West Point then was not what West Point is now. It was a somewhat shabby redoubt, one of many up and down the river that failed to halt the enemy. But the chain had succeeded. “The lesson was not that the chain was not a good idea, it was that the fortifications weren’t strong enough,” says Lt. Col. Sean Sculley, assistant professor of history and chief of the American Division at the U.S. Military Academy at West Point.

When Burgoyne was defeated at Saratoga and the British retreated to New York City, Washington ordered an even bigger chain in 1778. There are differing opinions on where the iron for the Chain was mined: Sculley says the iron was mined in New Jersey and other areas, while Doc Bayne, president of the Friends of Sterling Forest, says all the iron was mined in Sterling Forest. It was smelted at the Sterling Furnace, according to Bayne, and the pig-iron bars were taken to secret forges to be forged into links (see sidebar). The links were brought by oxen sleds to New Windsor, assembled in chains of 10 links, and floated on rafts to West Point. “Machin was in charge,” Sculley says. “He was the expert.”

Meanwhile, the Polish-born engineer Thaddeus Kosciusko was charged with building West Point — “not to fire on ships, but to defend the chain from assaults by land,” Sculley says. “They had learned from what Henry Clinton had done, so they built the fortification on high ground to defend it.”

Since the links were hand-forged, they varied in length: For example, some of the links that still exist today measure 19 inches long, while others are as long as 36.5 inches. As a result, the actual number of links in the Chain is unknown. Each link weighed more than 100 pounds, and the finished chain (with accompanying attachments and anchors) weighed 75 to 80 tons. It floated on wood rafts, with a wood boom south of the chain to prevent ships from trying to ram it. It could be disconnected in the center to allow friendly traffic through, and was taken out in the fall — so ice didn’t break it — and returned in spring.

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Gen. Benedict Arnold | Photo by the U.S. National Archives and Records Administration

And it worked. “It protected the Hudson Valley from the kinds of raids Clinton routinely practiced on the Connecticut shore during the war,” Sculley says. “The significance of that is hard to overestimate.” Johnson adds that, “By blocking the Hudson River to British ships, the Great Chain was the center of gravity — or long pole in the tent — for Fortress West Point.”  Indeed, the British regarded the Great Chain so critical to victory that they were willing to pay a malcontent American general named Benedict Arnold to deliver the plans of the fortifications at West Point.

“It was so important to Clinton he paid Arnold 20,000 pounds and gave him a generalship even though he failed and the plan was foiled,” Sculley says. “That was a lot of money to give and he failed to deliver what he promised.”

At West Point’s Trophy Point, the remaining 13 links, a swivel, and a clevis of the Great Chain are symbols of early West Point and the Hudson River, which John Adams knew as the North river and called the “key to the whole continent.”

A historical marker of the Great Chain exists on Constitution Island near West Point with a few remaining links displayed. | Photo by Doc Bayne

“Militarily, the Great Chain proved that deterrence works because, as a part of Fortress West Point, it appeared strong enough with its supporting fortifications to dissuade the British from attacking it,” Johnson says. As such, the chain deserves a more prominent place in the history of the American road to independence.

Related: What Did the Hudson Valley Look Like During the Age of the Dinosaurs?

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