When bunkering at a dock, which of the following signals must be displayed?

When bunkering at a dock, it is essential to display a red flag by day and a red light by night to signal the presence of a bunkering operation. This protocol is critical for ensuring safety and awareness among other vessels and personnel in the vicinity. The red flag during the day serves as a clear visual warning that bunkering is in progress, indicating a potential hazard due to flammable materials being transferred. Similarly, the red light at night continues to convey this message, ensuring that those operating or navigating nearby are alerted to the ongoing bunkering activities.

Using a red flag and red light helps establish a uniform standard that maritime operators can recognize, helping to prevent misunderstandings that could lead to accidents or unsafe situations. Adhering to this signaling guideline facilitates effective communication about the operational status of the vessel on a busy dock or wharf.