Abstract: A marine warning sign, in the shape of a right prism, having a frame forming a square of other polygonal shaped enclosure with straight sides and open front and rear faces. In the front face is positioned an assembly comprised of a transparent panel under which is a graphics panel. On the obverse face of the graphics panel is printed some desired warning indicia. A rear panel enclosed the rear face of the frame. A border, in the same shape as the frame, surrounds the indicia. The border is formed of electroluminescent tape. The electroluminescent tape illuminates when energized by an electrical power control located within the sign. The electrical power control is powered by a rechargeable battery which powers an a/c to d/c inverter. The electrical power control is switched on and off during night and day, respectively, by a circuit in the electrical power control comprised of a comparator having a bridge circuit with a photoresistor as one input.