Where it is impracticable for a seaplaneThe word 'seaplane' includes any aircraft designed to manoeuvre on the water. or a WIGThe term 'Wing-In-Ground (WIG) craft' means a multimodal craft which, in its main operational mode, flies in close proximity to the surface by utilizing surface-effect action. Are you interested in learning more about WIG craft? Find out more here - What are wing in ground craft? More craft to exhibit lights and shapes of the characteristics or in the positions prescribed in the Rules of this Part she shall exhibit lights and shapes as closely similar in characteristics and position as is possible.