I was puzzled by what I saw at the waterfront today. The Coast Guard helicopter in this shot made a couple of passes by an incoming ferry, then headed north, several piers up from where I was. The helicopter's rotors where making a discomforting high-pitched whine. A small Coast Guard ship followed along beneath the helicopter. I could make out a crowd of people watching from the pier, though it looked like a tugboat was parked up against the pier to block their view. The helicopter came down over the Coast Guard boat and lowered something on a line down to them. Then it moved away from the boat and went up close to the pier. An alarming puff of red gas came up out of the water and rose up against the side of the tugboat. The helicopter lowered a line into the water and then pulled it out, along with a person. As soon as the person got into the helicopter, the Coast Guard boat headed back south, past me, and the tugboat moved out into the bay. The helicopter hovered out there for a minute, the sound of the rotors switched from the high whine to a regular helicopter's thump-thump-thump-thump, and it headed back past me to the south. Whatever happened was done happening.