The key element of the West Point/Constitution Island fortifications
was the "Great Chain" affixed across the river as of 30 April 1778.
Ships which successfully negotiated the bend in the river would still confront
the chain barrier, which was expected to bring them to a dead stop, thus
facilitating engagement by batteries on the river banks.
The West Point chain was forged at Sterling Ironworks in Warwick, NY.
It was approximately 500 yards in length, composed of two foot long, 2.25"
thick iron links, each of which weighed 114 pounds.
Links of the original West Point Chain displayed at Trophy
Point. See Bic pen at left of center front link for scale.
The entire chain weighed in at 65 tons and required 40 men four days
to install. The chain floated on rafts assembled from 4 16' sharpened
logs, anchored between Constitution Island and West Point.
A log boom was also constructed, but after early problems with rot,
the boom was apparently kept on shore and only deployed when British attack
was thought to be likely.
View from Ft. Arnold looking toward east anchor point of Chain on Constitution
How imposing a barrier the chain actually was remains a subject of debate.
In the course of his correspondence with the British, Benedict Arnold (perhaps
not the most trustworthy source) claimed that a well-loaded ship could
break the chain. More recent research suggests that the chain would
indeed have been vulnerable to a loaded sloop or frigate. The British
chose not to risk a ship to make the attempt, however.