How do you get an 80-foot mast under a 65-foot bridge?

Answer: It takes a big pair of balls.

The video was taken somewhere on the InterCoastal Waterway around 2007. See a longer version here, and another vantage point here.

The original poster explains that the balls, each containing a tonne of water, are swung out with an initial turn of the boat to port or starboard. At that point, the boat tends to continue heeling on its own, but the degree of list can be controlled by extending the line holding each bag, using a winch in the cockpit.

H/T: Eliot Frosst