Iron Ship, Patent Model
date: label: date made
content: 1842
label: patent date
content: 1842-05-07
label: patent date
content: 1842-10-14
name: label: inventor
content: Kerr, James
label: inventor
content: Grant, William
label: inventor
content: Potter, John
notes: label: Description
content: James Kerr, William Grant, and John Potter of Pittsburgh, Pennsylvania, used this two-part model to demonstrate their 1842 method for lining the hulls of iron vessels with watertight chambers.
label: Description
content: Iron shipbuilding was in its infancy when James Kerr, William Grant, and John Potter came together to patent their improved iron hull in 1842. American ship owners were particularly slow to adopt iron (and later steel) for their hulls because the nation's abundant forests and wealth of skilled carpenters made wood construction significantly more cost effective. Nevertheless, those few iron vessels that were built in the 1840s and '50s-almost all of them British-tended to receive considerable attention in the press. Even European reporting circulated widely in the United States, brought over by express steamship and transmitted internally by riverboat. Perhaps it is not surprising, then, to find Kerr, Grant, and Potter familiar with "the usual way" of building iron vessels: covering a skeleton of angle-iron ribs with horizontal rows of iron plate, "as is now generally done." Their idea was to line the interior of such a structure with additional plates. The spaces between these inner and outer plates would form watertight chambers between the ship's ribs. The chambers would render "the vessel more buoyant if she sprang a leak, as each chamber was insulated from the others. "It will thus be evident that should the outer sheathing of the vessel be injured between any two or more of the ribs, that chamber only will fill with water, the rest of the vessel continuing to retain its buoyancy." In addition, this inner lining of sheet iron would make the hull more stiff, "and the necessity for bulkheads is entirely superseded."
label: Description
content: A reissue of Kerr, Grant, and Potter's patent in October 1842 incorporated a fuller description of their idea. The main revision it outlined called for the interior plates be bolted to the ribs, instead of riveted, in order to facilitate inspection and maintenance.
label: Location
content: Currently on loan
place: label: Associated Place
content: United States: Pennsylvania, Pittsburgh
topic: label: Subject
content: Patent Models
setName: label: See more items in
content: Work and Industry: Maritime
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content: America on the Move
label: See more items in
content: Transportation
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: TR.308545
label: catalog number
content: 308545
label: accession number
content: 89797
label: patent number
content: 2,612
objectType: label: Object Name
content: patent model, ship, iron
label: Object Type
content: Patent Model
label: Other Terms
content: patent model, ship, iron; lifeboat; Maritime
physicalDescription: label: Physical Description
content: copper (overall material)
label: Measurements
content: overall: 29 1/2 in x 6 1/2 in x 4 1/2 in; 74.93 cm x 16.51 cm x 11.43 cm