Rule 23 provides regulations for which type of vessels?

Rule 23 of the COLREGs specifically addresses vessels that are fishing. It outlines the responsibilities of fishing vessels concerning their navigation and interactions with other types of vessels. When operating in a fishing capacity, these vessels must display appropriate lighting and markings to indicate their activity and to ensure that other vessels can recognize them as fishing vessels.

This rule is crucial as it helps prevent collisions while fishing, particularly in areas where fishing boats are concentrated and may be less maneuverable than other types of vessels. The regulations also aim to ensure safe practices when navigating near other vessels, thus enhancing maritime safety.

In contrast, the other options refer to vessel categories that are governed by different sets of COLREG regulations. For example, while passenger vessels and commercial cargo vessels each have their navigational rules, they do not fall under the specific provisions set out in Rule 23 for fishing vessels. Moreover, the rules concerning vessels under sail pertain to sailing vessels and their interaction with powered vessels, demonstrating that each category of vessel has tailored regulations within the COLREGs.