Navigation light side of the vessel, a flashing green on the starboard side of the vessel, two flashing white lights on the top and one flashing yellow on the bottom side of the fuselage. The SpaceX Dragon cargo spacecraft also features a flashing strobe along with red and green lights. Navigation light A navigation light, also known as a running or position light, is a source of illumination on a vessel, aircraft or spacecraft. Navigation lights give information on a craft's position, heading, and status. Their placement is mandated by international conventions or civil authorities. Navigation lights are not intended to provide
Ship motions or "roll axis", is an imaginary line running horizontally through the length of the ship, through its centre of gravity, and parallel to the "waterline". A roll motion is a side-to-side or port-starboard tilting motion of the superstructure around this axis. There are three special axes in any ship, called vertical, transverse and longitudinal axes. The movements around them are known as roll, pitch and yaw. There are methods for both passive and active motion stabilization used in some designs. They include static hull features such as skegs and bilge keels, or active mechanical devices like counterweights, antiroll tanks and