Which rule emphasizes the need for vessels to be lit when at night?

The correct answer is indicative of Rule 27, which pertains to the lights and shapes of vessels engaged in fishing activities. This rule emphasizes the requirement for fishing vessels to display specific lights at night to signal their presence and activities to other vessels. These lights are crucial for ensuring the safety of navigation, as they help prevent collisions by making it clear to other mariners that a fishing vessel is in the area.

While other rules, such as Rule 22 (which relates to the visibility of vessels and the measures to take in poor visibility) and Rule 20 (which addresses the general principles concerning the application of the rules), also discuss lighting in context, Rule 27 specifically tackles the importance of appropriate lighting for fishing vessels and their operational status during nighttime. This helps to avoid dangerous encounters on the water, reinforcing the principle of visibility at night for safe navigation.