What is the vertical spacing of lights indicating a trawler is shooting, hauling, or hung up?

The correct answer relates to the established regulations for fishing vessels under the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs). Specifically, when a trawler is engaged in shooting, hauling, or if it is hung up, it is required to display specific lights that are set apart vertically. The spacing of these lights is crucial for visibility and ensuring that other vessels can recognize the trawler's activities.

The requirement for the vertical spacing of the lights that indicate these activities is not less than 0.9 meters. This measurement ensures that the lights are sufficiently separated to make the vessel's operation clear to other marine traffic, facilitating safe navigation and preventing collisions. The regulation aims to enhance visibility and ensure safety on the water, especially for navigating vessels that may not be familiar with the area or the types of fishing activities performed by trawlers.

In contrast, the other options indicate different measurements that do not meet the regulatory requirements for the vertical spacing of lights on a trawler. Therefore, only the choice corresponding to a spacing of not less than 0.9 meters aligns with the COLREGs' stipulations regarding the visual signaling of trawlers engaged in fishing operations.