Hello all, This info. was sent on another list serv and I thought it was fascinating enough to share with you. Laura Sisson-Thompson, Wisconsin. THE GREAT IRON CHAIN ACROSS THE HUDSON - Jack H. Westbrook -------------------------------------------------- (L. Diamant's book, "Chaining the Hudson", Carol Publishing, 1989) In 1778, during the Revolution, as a defense against British naval incursions up the Hudson River, a 1700' iron chain was made in New York State and emplaced across the Hudson at West Point. It was one of the longest and largest chains ever forged and remarkably constituted not only a military and metallurgical success but also a triumph of ad hoc management involving mass production, numerous contractors and subcontractors, interchangeable parts, and quality control, all advanced concepts for the 18th c. In the 1700s the use of iron chain was a new idea in military defense. Early in the war, chains had been put across the Richelieu River in Canada, at the narrows at Ticonderoga, and across the Hudson at Fort Montgomery. These had all failed, either metallurgically or because their emplacement locations were outflanked. General James Clinton in Nov 1777, following up on an earlier suggestion by Jacobus Van Zandt, recommended production and installation of a new, very heavy chain at West Point. George Washington himself chose 32yr - old Lt. Thomas Machin to be the engineer in charge of the project. Machin (1744-1816) had been a participant in the Boston Tea Party, wounded at Bunker Hill, and had helped place the captured cannon brought from Ticonderoga to Dorchester Heights outside Boston. He had little formal education and his engineering experience was limited to 4 years as assistant surveyor and paymaster for an English canal project and an even briefer experience as a mining consultant on a study that brought him to America. Nonetheless he had earned a reputation as a prototypical "can-do" engineer. As the first step, Machin and Deputy Quartermaster General Hugh Hughes studied the available iron manufacturers of New York and chose Sterling Iron Works (Peter Townsend, proprietor) in Orange Co. as prime contractor. A detailed 3-page contract was drawn up and signed on 2 Feb 1778 which provided for design and specifications for the chain, 9 months exemption from military service for the workers, an outside quality control board, and payment amounts and delivery schedule. The chain was to be made of 2 1/4" square bar, forged into links 31 1/2" long on average and 10" wide, weighing about 130 lbs. each. 750 links were required, together with 8 swivel pieces to prevent twisting and 80 clevises to connect individual sections of the chain. Each section of 8 or 9 links, weighing about 1/2 ton, had to be hauled in mid-winter on sledges or wagons, depending on the weather, by 2-yoke of oxen 30 miles north up Central Valley to New Windsor, south of Newburgh. There the sections were joined together with the clevises and pins at Brewster's forge on the south side of Murderer's Creek, stapled to huge 2' d., 16' long logs, and floated down the Hudson to West Point. The price paid Sterling for the chain itself, not including anchors and incidental hardware, was $92,000 (about $10 million in today's money). The Sterling works consisted of their own magnetite iron ore mine, a cold-air blast furnace equipped with a pair of water-powered bellows, 8 fining forges, and 10 welding units. The furnace produced cast iron pigs, 3 to 10' long, 4-5" thick, weighing 135-1000 lbs. each. These were then reheated in a finery forge to burn out the excess carbon. The pig was slowly fed in, melted into a pool on the hearth, and reacted with the oxygen of the air. The process was repeated two or three times, the melting point increasing as the carbon content was reduced. The finery product was a bloom that was then heated and hammered using a water-powered trip- hammer to form a dumbbell-shaped ancony. The final step in producing the wrought iron bar was at the chafery forge where the bulbous ends of the ancony were reduced to uniform size, and the bar elongated and worked to effect a favorable disposition of the slag stringers within the bar. Next, under another trip-hammer, the bars were scarfed (flattened at the ends for subsequent welding), bent around a giant mandrel while hot, and the scarfed ends welded to create a link. The work went on 24 hrs. a day, employing 60 iron workers, and an almost equal number of miners, wood cutters, and teamsters. This tremendous effort resulted in completion of the enormous project in a matter of weeks; the chain was in place across the river by 30 April 1778, an incredible accomplishment! It was fastened at each shore by huge, sunken, stone-filled wooden cribs and further strengthened by anchors. The hazards of winter's ice required the chain to be hauled out each November and re-emplaced the following March by a man-powered capstan, designed and built by Machin for this express purpose. The chain was an outstanding success; in place for five years, it was never broken by current, tides, ice, or British warships. After the War the chain was disassembled, sold for scrap, and remelted. But few of the original links remain today: 13 are in a memorial on the grounds of the West Point Military Academy; 10 others are known to exist in various museums; three such are mounted on the marble wall of the rotunda of the old NYS Educational Building in Albany. Altogether the chain project was, for its time and any time, a remarkable engineering and industrial achievement in design, productivity, and management organization and coordination. More detail on the project can be found in L. Diamant's book, "Chaining the Hudson", Carol Publishing, 1989, on which much of this account is based.