Many thanks to Ted Olsen for these images. When I hear “canal lock,” I think of miter gates, which some people attribute to Leonardo da Vinci, as here. The term comes from the fact that they are mitered. The active Barge Canal uses miter gates at all the locks except one. Know which? Answer follows.

The Enlarged Erie lock 56 in Lyons NY used a different type of gate.

Can you you tell what’s different about this lock? The gate is still visible, preserved under water.

It’s a drop gate.

Are drop gates used anywhere in the world today? I don’t know the answer.

The Barge Canal uses miter gates at all the locks except at lock 17, which uses a guillotine gate. Possibly the earliest lock gate is called a flash gate. The original gates at the Panama Canal are miter gates, and the ones in the expanded Panama are rolling gates.

More Lock 17 here.

Many thanks to Ted for these photos.