M15934.61 | Pont Victoria, derrick Chaffey, 1859

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Pont Victoria, derrick Chaffey, 1859
J. Dunbar
1860 (published), 19th century
Ink on paper - Lithography
58.6 x 88 cm
Gift of Mr. David Ross McCord
© McCord Museum
Keywords:  Architecture (8646) , bridge (558) , Print (10661)
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Keys to History

The Chaffey derrick was a Canadian invention devised by Benjamin Chaffey, who had contracted in canal construction for years in Canada and was responsible for all masonry on the southern half of the bridge. This compound derrick, powered by horses or steam, served as a prototype for the steel derricks used in high-rise construction today. It consisted of a wooden mast eighty feet tall, terminating at its lower end in an iron pivot which allowed 270º rotation. About sixty-five feet up from the base was a horizontal arm which supported a "travelling jennie". The jennie or carriage travelled back and forth on rails along the arm and contained gears to control the hoisting of the stone from the deck below, the movement of the jennie along the arm, and the rotation of the mast.

Remarkable for its ease of operation the derrick could, with great speed and accuracy, raise a stone weighing up to eleven tons from the barge, swing it to the pier site and lower it into position for the waiting masons. Furthermore, it was easily operated by "an intelligent boy."