Upstream drop gate of Lock 9 at Mile 8.7 on the Chesapeake and Ohio Canal towpath
Lock 9 is located at Mile 8.7 on the C&O Canal towpath. It is within sight distance of Lock 10 where there is a parking area for a dozen cars. See the Locks and Lockhouses web page for an interactive location map.
Lock 9 is one of seven locks within a 1.1-mile span of the Chesapeake and Ohio Canal, all of which are appropriately known as the Seven Locks. It is also one of the very few locks that has an upstream drop gate and not a typical miter gate. A miter gate has two doors that meet at an angle pointing upstream. The pressure of the water keeps them shut naturally. A drop gate, on the other hand, is a single door that opens by falling in the upstream direction like a tailgate on a pick-up truck and closes by being hoisted back in place with mechanical gears. It cannot fall downstream because it rests against notches in the stone retaining walls of the canal.
Illustration of a drop gate
Backside of the Chesapeake and Ohio Canal’s Lock 9 drop gate
The upstream gate was converted to a drop gate when the entire lock was lengthened ten feet on the upstream end so it could accommodate larger boats. I assume the C&O Canal Company figured that if a new gate had to be built anyway, might as well try out the drop gate technology. Only a few locks in this area were enlarged, and the longer boat idea never gained much ground.
Drop gate hardware of Lock 9 on the Chesapeake and Ohio Canal
The downstream end of the lock was never modified, and the miter gate remained in place.
Downstream view of the Chesapeake and Ohio Canal from Lock 9
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Last updated on June 21, 2024
