If a vessel is unsure whether it is overtaking another, what should it assume?

The appropriate action in a situation where a vessel is unsure whether it is overtaking another is to assume that it is indeed overtaking. This approach is rooted in safety and the principle of prudence at sea, particularly under the COLREGs (International Regulations for Preventing Collisions at Sea).

If a vessel is unsure, assuming that it is overtaking means it should take the necessary precautions to avoid a potential collision. The COLREGs place great emphasis on the responsibilities of vessels when it comes to navigating and the interactions between them. When a vessel is overtaking another, the overtaking vessel is required to keep clear of the other vessel, ensuring that it does not pose a risk of collision. Thus, having this assumption encourages the vessel to act conservatively and prioritize safety, ensuring that it adheres to the regulation that governs the conduct of vessels in such situations.

Assuming that it is overtaking when unsure helps to foster a culture of caution and responsibility among mariners, which is critical for the safety of all vessels navigating in proximity. This is why the correct choice reinforces a safety-first approach in maritime navigation.