The gates of a lock chamber function as doors, letting boats in and out of the lock. Weighing approximately 1 ton per rail, these gates were originally constructed of oak from stands along the Rideau. The depletion of oak stands here in Ontario has forced the importation of Douglas Fir from British Columbia for gate construction today.
A set of gates lasts approximately 12-15 years. Today gates are constructed at the shops in Smiths Falls, taking as long as 2 months to make 1 set of gates(2 doors). Originally they were constructed on site, at the locks, by carpenters and blacksmiths.
Gates are opened and closed using a winch on the side of the wall called a 'crab'. The name refers to the animal and its ability to pinch your fingers. These gate crabs have a series of chains attached between them and the gate, which allows the gate to open and close when cranked. Below are a few activities you can do to learn more about these gates. The activities relate to the evolution of the gate mechanisms and their technology.
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Students will learn about the various gate mechanisms used on the Rideau Canal in the past and present through the study of diagrams and descriptions of each gate mechanism.
Lock mechanism diagrams
Newspaper clippings (Resources)
1. Have students work in a groups of three or four. Provide them with the four gate opening mechanism pictures and the four descriptions to match. Study the four pictures of gate mechanisms provided. The four descriptions below match one of these pictures. They are all different. Look carefully at the crab and the way in which it is opening the gate. Read the descriptions and try to match them up.