Wanted: Illinois & Michigan Canal Workers
Information for Locktender
How an Illinois and Michigan Canal Lock Worked
Boats entered or left an I & M Canal lock through two large wooden gates that opened like double doors at either end of the lock. But the water that raised or lowered boats within the lock flowed through the small iron valve gates. There was one such valve gate in the bottom quarter of each of the four large wooden gates on an I & M Canal lock.
When "locking through" a boat approaching from upstream, the locktender began with the large wooden gates at the lock’s downstream end closed and those at the upstream end wide open. After the boat moved into the lock, the locktender closed the upstream gates behind it. He then opened the downstream valves gates, allowing gravity to drain water from the lock chamber into the downstream pool. Within a few minutes, the water level inside the lock chamber was the same as that downstream from the lock, and the locktender could close the valve gates and open the large downstream gates, enabling the boat to leave the lock. When a "locking through" a boat approaching from downstream, the locktender simply reversed the process and allowed water to enter the lock from the upstream level via the two valve gates located in the upstream lock gates.
(Illinois and Michigan Canal, no pp.)
Historic Illinois
December 1979
Mary Yeater Rathbun
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