What vessels should a sailing vessel underway keep out of the way of?

A sailing vessel underway should keep out of the way of a vessel restricted in her ability to manoeuvre. According to the COLREGs (International Regulations for Preventing Collisions at Sea), vessels that are restricted in their ability to maneuver include those engaged in underwater operations, laying pipelines, or those constrained by their draft in a narrow channel. These vessels cannot take action to avoid collisions due to their operational constraints, thus the responsibility falls on other vessels, including sailing vessels, to keep clear.

Understanding the implications of the other options is important. A vessel that is anchored is not moving and does not pose a direct risk of collision to a sailing vessel underway. Similarly, a vessel engaged in recreational activities may not necessarily be maneuvering in a way that requires a sailing vessel to alter its course significantly. Lastly, a vessel under command refers to a power-driven vessel that is capable of navigating freely and is primarily expected to take evasive action when necessary. Thus, it is the vessel restricted in maneuverability that requires utmost consideration by a sailing vessel.