Turn of the lock

Last year San Antonio installed state of the art 18th Century technology with a set of locks on the San Antonio River. Like the locks on the Panama Canal, they operate on gravity to raise and lower tour boats and water taxis about nine feet up and down. This feat does require the attention of a lock tender to open and close valves and doors. At one point a spectator had to knock on his window to point out that there was a boat waiting in the lock. These locks have been operating less than a year, so perhaps they still don't have all the kinks worked out.