From 1885 to 1929, fifty-one dams were built across the Ohio River to maintain a minimum 9 foot channel depth, and boats passed through locks to get around each dam. When a boat went up the river, the upstream gates were closed and the drain valve was opened so the lock chamber emptied by gravity, then the downstream gates opened to let the boat enter. After the drain valve and downstream gates were closed, water entered through the fill valve until it matched the water beyond the upstream gates, and then the upstream gates opened so the boat could leave the lock chamber and continue upriver; the procedure was reversed for a boat going downriver. Ralph Lindsey recalled that one boat crew always passed him a bag of coffee as they locked through. In 1964, a barge moving too fast into the lock knocked the roller gates off their track, and because the Meldahl Dam was nearly completed, repairs were never made and Chilo Lock and Dam closed forever. The Chilo lock was controlled from the powerhouse, where large air tanks on the third floor provided the pressure to open and close the gates. Chilo used roller gates instead of miter gates; the wooden gates rested on iron wheels and were pulled along their tracks by wire ropes wound on drums. Roller gates gave boats more room to pass, but sediment easily collected around the wheels, causing them to jam or derail, and although many roller gates were replaced with miter gates, Chilo kept its roller gates throughout its operation.