A daylight signalling lamp on a ship, also known as an Aldis lamp, is a specialized lamp used for optical communication by transmitting white light signals in focused beams visible by day and night. It allows ships and shore stations to communicate using Morse code or light signals, especially during navigation for safety and signaling purposes. The lamp is required on ships over 150 tons engaged in international voyages and must not solely depend on the ship's main power source. It typically ha