Requirements for Towing a Person With a Vessel All vessels towing a person(s) on water skis, an aquaplane, or a similar device must have a person on board, in addition to the vessel operator, observing the towed person(s) at all times. If towing a person behind a personal watercraft, the PWC must be at least nine (9) feet in length and be rated for three people—the operator, the observer, and the retrieved skier. All persons being towed behind a vessel on water skis or any other device must wear a U.S. Coast Guard–approved PFD. Ski belts are not U.S. Coast Guard–approved. Persons may be towed behind a vessel on water skis or any other device only during daylight hours only.