How to Make a Harbor Donut

It's pretty common to see Coast Guard gunboats accompanying the Staten Island Ferry. Yesterday, one off the Brooklyn (starboard) side of a South Ferry-bound boat elicited from tourists such a flurry of "oohs," pointing, and cellphone photographs that I thought someone had sighted a whale in the harbor. Earlier in the week, from the same spot, I made these photographs of what should be a pretty fun maneuver as the boat cuts back to cover the other side of the ferry.