Hudson River Chain The Hudson River Chain refers to two chain booms and two " chevaux de frise " constructed from 1776 to 1778 during the American Revolutionary War across the Hudson River as defenses to prevent British naval vessels from sailing upriver . These defenses along the Hudson River were overseen by the Highlands Department of the Continental Army . The most significant and successful was the Great Chain , constructed from West Point in 1778 , and used through 1782 after the war ' s end . The huge links for the chains were forged at iron works in Orange County , New York . Background . Both the Americans and British knew that passage on the Hudson River was strategically important to the war effort . Americans worked to devise plans to slow or block ship passage on the river , planning to attack enemy ships by cannons and mortar located at existing defensive forts or those to be constructed . It eventually constructed such obstacles across the river at northern Manhattan , between forts Washington and Lee in 1776 ; at the newly constructed Fort Montgomery on the West Bank on Popolopen Creek in 1776 – 1777 south of West Point ; a partially completed one at Pollepel Island in 1776 – 1777 north of West Point ; and the Great Chain ( 1778 – 1782 ) at West Point . The largest and most important project was the latter chain at West Point , which was reset each spring until the end of the war . Attention was concentrated on the West Point area because the river narrowed there , and curved so sharply that , together with winds , tides and current , ships already had to slow to navigate the passage . Creating more obstructions on the river would enable the shore batteries to work their cannons against the enemy . Fort Washington ' s " chevaux - de - frise " ( 1776 ) . As part of the barriers erected across the river , the Army constructed a " chevaux - de - frise , " an array of logs sunk underwater , between Fort Washington on the island of Manhattan , and Fort Lee across the river in New Jersey . The logs were intended to pierce and sink any British ships that passed over it . An opening was left for the passage of American ships . As the British learned of the opening from a local resident , they successfully passed through the barrier several times . The British captured Fort Washington on November 16 , 1776 , rendering the defensive barrier moot . Fort Montgomery Chain ( 1776 - 1777 ) . A chain and boom were stretched across the river from Fort Montgomery on the West Bank , at the lower entrance to the Highlands just north of the modern - day Bear Mountain Bridge , to Anthony ' s Nose on the East Bank . Fort Clinton had been built just south of Popolopen ' s Kill ( or Popolopen Creek ) and also on the West Bank . Captain Machin headed this effort . In November 1776 , a faulty link broke under stress induced by the river tides , highlighting some of the difficulties of trying to chain the Hudson . It was repaired and reset . After the British captured forts Montgomery and Clinton on October 6 , 1777 , they dismantled the chain and raided upriver as far as Kingston . Governor Clinton , one of the committee assigned by the New York Convention to devise means of defending the Hudson , was heartened as the British never attempted to run ships through the chain . He concluded that the basic idea of obstructing the river seemed sound . After Captain Machin recovered from wounds from battle with the British , he began work on the stronger Great Chain at West Point , which was constructed and installed in 1778 . Pollepel Island ' s chevaux - de - frise ( 1776 - 1777 ) . Another chevaux - de - frise was constructed across the Hudson between Plum Point and Pollepel Island , north of West Point . The defenses were never fully completed , and its importance was overshadowed by completion of the Great Chain at West Point the following year . The Great Chain ( 1778 - 1782 ) . In the spring of 1778 , a heavy chain supported by huge logs was stretched across the Hudson from West Point to Constitution Island , opposite . It was constructed at the Stirling Iron Works , in Warwick , Orange County , and chain links from Long Pond Iron Works in Ringwood , New Jersey . The task was completed in six weeks . The Hudson River ' s narrow width and sharp turns at West Point created adverse sailing conditions . The Army took advantage of this by constructing The Great Chain in 1778 as an obstacle to the movement of British ships north of West Point . The distinctive " S - Curve " of the Hudson at this point would force any large ship to tack in order to navigate it . American soldiers positioned the chain to impede the progress of a ship should it attempt to turn into the east - west channel against the strong current and frequently unfavorable winds . Part of the estuary of the Lower Hudson River , this area is subject to significant tides , making navigation by sailing vessels particularly difficult . Cannons were placed in forts and artillery batteries on both sides of the river to destroy ships when they slowed to a halt against the obstacle . When finally completed , the 600 - yard chain contained huge iron links , each two feet in length and weighing 114 pounds . The links were carted to New Windsor , where they were put together , and floated down the river to West Point on logs late in April . Including swivels , clevises , and anchors , the chain weighed 65 tons . For buoyancy , logs were cut into sections , waterproofed , and joined by fours into rafts fastened with timbers . Short sections of chain ( 10 links , a swivel , and a clevis ) were stapled across each raft and later , in the river , the chain sections were united . Peter Townsend was paid a great sum of money from the Continental Congress for manufacturing the chain . Captain Thomas Machin , the Artillery Officer and engineer who had installed the chain at Fort Montgomery , was assigned to the same task at West Point . On 30 April 1778 , he directed the installation of the chain across the river . Its southern end was secured to a small cove on the West Bank of the river and its northern end was anchored to Constitution Island . The West Point side was protected by Chain Battery and the Constitution Island side by Marine Battery . Both ends were anchored to log cribs filled with rocks . A system of pulleys , rollers , ropes , and mid - stream anchors were used to adjust the chain ' s tension to overcome the effects of river current and changing tide . Until 1783 , the chain was removed each winter and reinstalled each spring to avoid destruction by ice . A log " boom " ( resembling a ladder in construction ) was built to span the river about downstream ( south of the chain ) to absorb the impact of any ship attempting to penetrate the barrier . The British never attempted to run the chain . Benedict Arnold claimed in correspondence with the British that " a well - loaded ship could break the chain . " The greater system of fortifications at West Point , of which the chain was part , was designed and built by the Polish engineer Tadeusz Kościuszko . After the revolution , the portion of the chain not saved was " relegated to the West Point Foundry furnaces near Cold Spring , New York , to be melted down for other uses . " The saved chain portion was first displayed at the West Point ordnance compound , along with a captured mortar ( cannon ) , as shown in the black and white drawing to the right , which was made in 1905 . More recently , it has been displayed at Trophy Point , where the chain surrounds a pile of rocks . The thirteen links of the chain represent each of the original states ; the display includes one swivel and one clevis . The exhibit is maintained and preserved by the West Point Museum . Recovered in 1855 from the river , a section of the boom is displayed at Washington ' s Headquarters State Historic Site in Newburgh , New York . Capitalizing on pride in the audacious engineering project , John C . Abbey , and later Francis Bannerman , sold counterfeited chain links to collectors and museums .