Video
Locking Through (Video)
Transcript
Boats travel easily along the flat water sections of the C&O Canal but elsewhere they faced a challenge: the 605 foot elevation change over the length of the canal. So a series of 74 lift locks had to be built to carry the boat up and down the steeper terrain. A lift lock works like a water elevator, raising or lowering the boat. A series of locks along the canal are placed like stair steps, up and down the landscape.
This boat is headed downstream. The water level in the lock must be the same as the level the boat has been traveling on. Once the boat is inside the lock it is tied off to snubbing posts, to keep it from ramming and damaging the gates or the boat itself, then the gates behind it are closed.
A large balance beam is used to close the lock then a lock key opens the butterfly or wicket valves in the downstream gates allowing the water to slowly drain out of the lock. As the water drains, the boat is gradually lowered to the next level. By the time the water levels are equalized the boat has dropped about eight to ten feet.
Then the large wooden gates of the downstream side can be opened. It has taken ten to fifteen minutes to complete the process, since operation is easier with two people. Having stepped down to a new water level the boat will be hitched again to the mules and the cargo and crew are on their way.
Description
Watch a canal boat use a lift lock in this short, captioned video. Animations help illustrate how these simple engineering structures conquered the terrain of Western Maryland.
Duration
2 minutes, 4 seconds
Credit
National Park Service
Date Created
12/06/2013
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