Exceptional vessels rules

A vessel that has good reason to be avoided must let other boats know. For example a tug boat with barges may consider itself able to maneuver and change course to avoid a sailboat. Then be very upset if the sailboat thinks it must give way and does not hold course. At night exceptional vessels have colored light signals and daytime various shaped things that signify their ability to maneuver. The Christmas Tree Rule: if you see unusual colored lights at night or ornaments in daytime they are exceptional. Call them on the radio if there is any question of how to avoid them.