A Brooklyn teenager is presumed dead after a Jet Skiing accident in Mill Basin and authorities say it's a grim reminder that people need to be cautious on the water. Boaters in Sheepshead Bay say Jet Skiers sometimes get a little crazy when out on the water. According the U.S. Coast Guard, Jet Skis are required to follow no wake zones and other navigational markings. They say a lifejacket is required for everyone on a personal watercraft, including operators and riders. The Red Cross also suggests boaters pay attention to changes in the weather, pack an emergency kit with flares to signal for help, and have a portable radio. Regardless of age in the state of New York, anyone operating a boat or personal watercraft must take a boating safety course. It takes about eight hours of classroom instruction and many times it is offered for free.