When does Rule 15 apply?

Rule 15 of the COLREGs, often referred to as the "Crossing Situation" rule, specifically applies to power-driven vessels when they encounter other vessels in a crossing scenario. This rule states that when two power-driven vessels are crossing paths and there is a risk of collision, the vessel that has the other on its starboard side is the stand-on vessel, meaning it must maintain its course and speed, while the other vessel must take action to avoid a collision.

While it may seem intuitive for all types of vessels to follow this rule, it focuses on power-driven vessels, as these are typically involved in crossing situations where one vessel may have limited maneuverability due to its operational constraints, such as speed and stopping distance. Other vessels, like sailing vessels or vessels that are moored, fall under different rules and scenarios outlined in the COLREGs. This specificity ensures that power-driven vessels manage their navigational responsibilities effectively, thereby maintaining safety on the water.