Today I learned that the miter lock - the V-shaped pair of gates that control water levels in a marine environment – was invented in the 1490s by Leonardo da Vinci. 

I've seen working locks many times, from the mighty Soo Locks with their capacity to move 1000- foot freighters from lake to lake via immense 250-ton gates, all the way down to tiny DIY wooden portcullis canal locks in the countryside. 

I visited the Ballard Locks by land, and  chatted with the operators, passing yachters, and a delightful woman named Katie, who was, she told me,  Locks Volunteer of the Year.  I learned about the indigenous peoples who used this land pre-locks, the geology behind the installation, and learned the origins of the amazing miter lock, which uses water pressure to seal the transit chamber. Even the Panama Canal uses da Vinci's design.

I've been through these locks countless times.   As the  gravity powered water raises or drops you 22 feet in just a few short minutes, I'm busy keeping track of lines and fenders, stop and go lights, operator instructions like "stern to bollard 28", and keeping an eye on the other boats packed like sardines into the chamber rail to rail. In the controlled mayhem, I never had time to wonder who invented this engineering marvel.

Now I know who to thank: Leonardo da Vinci.