Taffrail Log Recorder, Patent Model
date: label: Date made
content: 1878
label: patent date
content: 1878-08-06
name: label: patentee
content: Massey, Edward E.
label: maker
content: Edward E. Massey
notes: label: Description
content: This high-quality working example of a Taffrail Log was submitted to the U.S. Patent Office when John Edward Massey, its British inventor, applied for a patent in 1877. This two-part mechanical log measures a vessel's speed though the water. The four-bladed rotator is towed astern and registers the distance traveled and speed on an integral dial. Closer to the ship, or even mounted to the ship's rail, a second mechanism measures rotations of the towing rope to record the same information. The rotator must be hauled in to be read, but the second log can be monitored while the first is still in operation.
label: Description
content: Since the sixteenth century, sailors had determined vessel speed using a log. This device was basically a rope with knots tied at intervals along its length. With a board attached to one end to create drag, the log-line would be heaved overboard and allowed to run out for a short period of time. The number of knots counted off during that time indicated the speed. (The unit of speed at sea is therefore the knot, one knot being equal to one nautical mile per hour). Logs provided vital information for navigation but were susceptible to a variety of errors, and inventors in the seventeenth and eighteenth centuries sought ways to improve their accuracy. Edward Massey, a leading London nautical instrument maker, received the first patent for a successful mechanical log (British patent 2,601, March 24, 1802), and many ships used his firm's "patent logs" throughout the nineteenth century. John Edward Massey inherited the business and continued to patent improvements to his father's work.
label: Location
content: Currently not on view
topic: label: Subject
content: Patent Models
setName: label: See more items in
content: Work and Industry: Maritime
label: See more items in
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.309317
label: catalog number
content: 309317
label: accession number
content: 89797
label: patent number
content: 206682
objectType: label: Object Name
content: Log, Taffrail
label: Object Name
content: log, taffrail, patent model
label: Object Type
content: Patent Model
label: Other Terms
content: Log, Taffrail; Maritime
physicalDescription: label: Physical Description
content: brass (overall material)