Which tool is necessary for signaling at night without using pyrotechnics?

The use of an electric light is essential for signaling at night without resorting to pyrotechnics because it provides a visible means of communication that does not require a flame or explosive components. Electric lights can be used to shine an illuminating signal, making it effective in both low visibility conditions and during hours of darkness.

Flares, while effective for signaling, are pyrotechnic devices and not allowed for this specific context. An orange flag is primarily used for daytime signaling and communication on the water but does not provide visibility at night. Smoke signals, similar to flares, rely on combustion and are not practical for nighttime signaling as their visibility is significantly diminished after sunset. Thus, the electric light serves as a safe and reliable tool for nighttime signaling, fulfilling the requirements without involving pyrotechnic elements.