According to the Rules, what operation requires a vessel to display two cones with their apexes together?

Displaying two cones with their apexes together is a signal that indicates a vessel is engaged in trawling operations. This configuration serves as a visual indicator to other vessels operating in the vicinity about the nature of the trawler's activities, specifically that it has fishing gear deployed in the water.

In the context of maritime navigation, signaling is crucial for safety, especially when fishing vessels are operating. It alerts nearby vessels that they should take care and avoid the area where the trawler is working, as it may have nets or lines that could entangle other vessels if they come too close.

Other operations, such as fishing, anchoring, or being moored, have their own specific signals and visual indicators that differ from the configuration of the two cones with apexes together. For example, a fishing vessel not trawling would display different signals, while anchoring requires a different setup altogether. Understanding these distinctions is vital for ensuring safe and efficient navigation on the water.