Wanted: Illinois and Michigan Canal
Workers
Information for Lock Builders
Lock 14 is a typical lift lock with a narrow inner "chamber" measuring 110 feet long by 18 feet wide, and having a minimum water depth of 56 inches. At both ends of the chamber were two wooden gates, each 19.75 feet high (at their mitre-posts) by 11 feet wide. Because the gains were wider than the chamber they served, when closed they formed of "V-shaped" barrier pointing upstream. (The floor of the chamber was covered with oak planking.)
To lock a boat through--in an upstream direction--the lock-tender would first open one of the two downstream gates, across the canal on the closed upstream set of gates (or a bridge, if present), and then open the second of the downstream pair. The boat now entered the chamber and the gates closed in reverse order. Moving to the upstream set the lock-tender now opened the butterfly valves (by way of control levers atop the gates) allowing water to enter the chamber. When the level of that water reached the level of the water in the upstream channel, these valves were then closed and the upstream gate subsequently opened.
It took about 15 minutes to lock boats through, but only one boat could be locked through at a time. In contrast to the lift locks the canal also had "guard" locks, which were locks that passed boats through with no substantial change in water levels. Guard locks were constructed at dams when it was necessary for a canal, sharing an impoundment with a river, to exit from that river (see map 3 on page 7). The guard lock not only controlled the amount of water passing into the canal, but also prevented refuge from washing into its channel.
Return to Wanted: Illinois & Michigan Canal Workers Lesson Plan