Which rule covers the conduct of vessels in restricted visibility?

The conduct of vessels in restricted visibility is covered by Rule 19 of the International Regulations for Preventing Collisions at Sea (COLREGs). This rule outlines the actions vessels must take when navigating through conditions where visibility is severely limited, such as fog or heavy rain.

According to Rule 19, all vessels must proceed at a safe speed that allows them to take proper and effective action to avoid collision and be able to stop within a distance appropriate to the prevailing circumstances and conditions. Additionally, it emphasizes the importance of using sound signals to communicate their presence and intentions to nearby vessels, which is critical when visibility is poor.

In contrast, the other rules mentioned address different situations. Rule 17 pertains to the conduct of vessels engaged in fishing and their interactions with other vessels, Rule 22 focuses on vessels not under command, and Rule 9 governs narrow channels. Each of these plays a pivotal role in ensuring safe navigation but does not specifically address the unique challenges posed by restricted visibility the way Rule 19 does.