A little while ago I posted a blog about the operation of a boat on the C&O canal in the area of Great Falls, the boat being pulled by mules walking along the towpath. When the boat gets to the lock at Great Falls, which is lock 20 on the C&O canal, the mules are unhitched from the boat, and the boat makes its way downstream through the lock following the process below.
As the boat approaches the lock, the upstream gates are in the open position and the gates downstream of the lock are closed so that the water in the lock is at the level of the water upstream of the lock. The boat enters the lock.
After the boat has completely entered the lock, the upstream gates are closed.
The next step is to open up the valves in the downstream gate so that water can escape downstream and the level of water within the lock can begin to go down.
After the water level has gone down to the level of the canal below the lock, the downstream gates are opened completely.
The boat now proceeds out of the lock.
And finally it is clear of the lock!
The National Park Service offers tours on the Charles F. Mercer on weekends between spring and fall.
Splattered Brains 