How is a vessel deemed to be overtaking another vessel?

A vessel is deemed to be overtaking another vessel when it is approaching from an angle greater than 22.5 degrees abaft the beam of the other vessel. This definition is important because it dictates the responsibilities of the overtaking vessel and the action it must take to avoid collisions.

When a vessel approaches from more than 22.5 degrees abaft the beam, it signifies that the overtaking vessel is moving into a position behind the other vessel and is, therefore, not considered to be on a collision course. This is significant in maritime navigation, as the Rules of the Road under the COLREGs distinguish between overtaking and crossing situations, impacting the actions required to ensure safe passage.

In contrast, if a vessel approaches from straight ahead or an angle less than 22.5 degrees abaft her beam, it is not considered overtaking. This distinction requires that vessels maintain their respective navigational responsibilities; for instance, the give-way vessel in a meeting situation must take action to avoid collision, creating different rules of engagement as per the COLREGs. Understanding these angles helps mariners make informed decisions regarding right-of-way and navigation safety.