It's crazy how small the locks are, I'd like to see the boats that went in them.
In non-Covid years you could even ride on one.
www.nps.gov
Small as they are, they're deep, and when they're closed the overspill forms an absolutely *vicious* hydraulic below the doors.
You know the Hollywood movie romantic trope of ducking just into a waterfall? You _really_ don't want to do it downstream of a closed canal door, and just one rescuer with a rope probably won't be enough.
Part of the reason they're small is that, during droughts especially, water had to be made up by steam pumps upstream, pumping from the main river.
Another reason they're small is that, in several spots including the Monocacy river, the canal had to be aqueducted across the stream gorges.
https://www.nps.gov/choh/learn/historyculture/themonocacyaqueduct.htm