2. The rightist tendencies of gondolas
Ever wondered why gondolas don't go round and round in circles?
In a rowboat, if you pull on the left oar (or push in Venice), the boat turns to the right. Pull on the right oar and it goes to the left. Without a rudder, that's how you steer a rowing boat.
The propulsion force for a gondola is a single oar always on the right side of the boat, yet it goes straight forward. Why?
The answer is simple, and when you know it, obvious. All gondolas are built with a curved keel, so that they always steer to the right. Put a motor on the back of a gondola and it will just go round in clockwise circles. The single oar pushing the boat to the left counteracts the natural tendency of the boat to steer to the right, so it goes straight. Clever.