Which signal is required to be displayed at night while discharging at a dock?

Displaying one red light at night while discharging at a dock is crucial for safety and proper maritime signaling. The use of a single red light serves as a warning signal indicating that a vessel is discharging cargo. This visual cue alerts other vessels in the vicinity that the operations may create hazards, necessitating caution.

In maritime operations, the color red universally denotes danger or a stop signal, making it an effective choice for nighttime visibility to ensure that other vessels or nearby shoreside operations are aware of the potential risks involved in the discharge operations. The placement and visibility of the red light are important as they help prevent collisions and ensure that all navigational parties are informed of the vessel's activities.

Other signals, such as green or white lights, do not convey the same level of warning and might lead to misinterpretation of the vessel's operational status. A flashing orange beacon may also indicate a warning but is not specifically required in this context regarding the discharge operations at a dock, which is why the red light is the proper signal to display.