Heritage
Troy iron and the building of the USS Monitor
An ironclad went from contract to launch in a hundred and one days, and the men who supplied its iron owned the works next door.
The Monitor is remembered for a revolving turret and a stalemate in March 1862. The part this journal keeps is quieter. Her deck was two layers of wrought iron, her hull plates were forged in Troy, up the Hudson, and the skin was held with rivets and bolts. Read as metal, the ship is a document of what mills and forges could do in 1861, and of how little time they were given.
Where did the iron come from?
The encyclopedia’s article on Henry Burden states the Troy connection plainly: his company forged the hull plates for the Monitor. Burden, a Scot from Dunblane trained in engineering at Edinburgh, had run the Troy Iron and Nail Factory on the Wynantskill Creek since 1822 and came to own it outright. He had been among the first to propose plate for ironclad seagoing vessels, and had sent specimen plates to Glasgow for testing. The Navy’s order found a shop that had already thought about the problem.
Assembly was spread across three shops. The hull rose at the Continental Iron Works in Greenpoint, Brooklyn, keel laid 25 October 1861. The turret was built at the Novelty Iron Works in Manhattan, taken apart, shipped over the East River and reassembled. The engines came from the DeLamater Iron Works, also in Manhattan. Ericsson, Bushnell, Winslow and Griswold signed as partners bound to share profits and losses equally.
Why five thin plates instead of one thick one?
Because the rolls could not spare the time. Ericsson had wanted either six plates of one inch or a single 4 in (100 mm) outer plate backed by three quarter-inch plates, but the thick plate required too much time to roll. As built, the sides of the raft carried three to five layers of 1 in (25 mm) iron over about 30 in (762 mm) of pine and oak. Three of the plates ran the full 60 in (1,524 mm) height of the side; the two innermost stopped short. The design followed the mill, not the drawing board.
Rivets inside, bolts outside
The fastening scheme is explicit in the record. The two innermost plates were riveted together; the outer plates were bolted to the inner ones. Where the innermost layer met itself in a butt joint, a ninth plate, 3/4 in (19 mm) thick and 15 in (381 mm) wide, was bolted over the seam. The deck wore two layers of 1/2 in (13 mm) wrought iron, the stuff of forge welding, though no joint in this armor was welded: plate met plate through bolts and rivets.
The shop that made her rivets goes unnamed in the record. What the Troy pages do publish is scale: the Burden works ran twelve rivet machines at eighty rivets a minute each, beside a rivet factory and a rivet warehouse. Whether those machines fed the Monitor is not stated. The armor, position by position:
| Position | Plate |
|---|---|
| Gun turret | 8 in (203 mm), 11 in (280 mm) in front of the gun ports |
| Waterline belt | 3 to 5 in (76 to 127 mm) |
| Deck | two layers of 1/2 in (13 mm) wrought iron |
| Pilot house | 9 in (229 mm) |
A hundred and one days, iron permitting
The contract was signed on 4 October 1861 for $275,000. Ericsson’s guarantee of delivery in a hundred days won the competition, though no navy had yet tested a revolving turret. Building ran in fits and starts, on short iron-delivery delays and occasional cash shortages. The hundred days elapsed on 12 January with the ship still unfinished, and the Navy declined to penalize the builders. Launch came on 30 January 1862, commissioning on 25 February. The botched trials and the naming of the ship are kept in the Wikipedia record of the vessel.
What the shot did to the plate
On 9 March 1862 Monitor fought the Virginia, the Confederate ironclad built on the scuttled Merrimack’s hull, for about four hours at ranges down to a few yards, the first battle between armored ships. Monitor was struck 22 times, nine hits on the turret, two on the pilot house, and she fired 41 shots back. Inside the turret, direct hits sheared bolts that ricocheted around the cylinder. Neither ship was seriously damaged, and Virginia came away with 97 indentations in her armor. The laminated plate held.
Lost off Hatteras, found at 230 feet
Ordered south in December, Monitor foundered on 31 December 1862 under tow in a storm off Cape Hatteras, her low freeboard and heavy turret ill suited to open water. Sixteen men were lost, forty-seven rescued. The wreck was located on 27 August 1973, 230 ft (70 m) down, upside down. In 1975 a half-nautical-mile radius around it became the Monitor National Marine Sanctuary, the country’s first. The turret broke the surface on 5 August 2002 after 41 days of work by some 160 divers, and guns, turret and engine are now at the Mariners’ Museum in Newport News, Virginia.
Reading a seam on dry land
Nobody meets a Monitor plate at the curb, but the shop logic survives in riveted ironwork within walking distance. Find a seam, count the layers under it, and look for the strap across the butt joints: on this ship that strap was a 3/4 in (19 mm) plate bolted over the joint. The former Burden office, a brick Romanesque Revival building of 1881 and 1882, still stands in South Troy. The iron around Albany and Troy outlasts any single afternoon, so plan the walk before the light goes.
The record itself
en.wikipedia.org/wiki/USS_Monitor is the free encyclopedia’s article on the first ironclad commissioned by the United States Navy. It carries the builders and the dates, the cost, the dimensions and the armor thicknesses, the account of Hampton Roads, the loss off Cape Hatteras, the rediscovery in 1973 and the recovery of the turret, engine and guns. The Burden firm’s hull plates are credited in the encyclopedia’s article on Henry Burden.