To be considered "engaged in fishing" according to the Rules of the Road, a vessel must be __________.

Answer: C — using fishing apparatus which restricts maneuverability

To determine if a vessel is "engaged in fishing" according to the Rules of the Road, it is essential to understand the concept of maneuverability restrictions due to fishing operations. The correct answer highlights that a vessel must be using fishing apparatus that restricts its maneuverability in order to be classified as engaged in fishing. When using gear such as nets or trawls, the vessel's ability to navigate freely is compromised, which is a crucial factor in defining when a vessel is considered engaged in fishing. This restriction in maneuverability is what distinguishes fishing vessels from other types of vessels that may simply be traveling or operating without an impediment to their navigation. In contrast, while catching fish or traveling at slow speed might be associated with fishing activities, they do not specifically indicate a vessel's status under the Rules of the Road. The use of nets only also does not define engagement in fishing, as other forms of fishing gear that might not involve nets can also cause maneuverability restrictions. Therefore, the focus on fishing apparatus that limits maneuverability provides a clear guideline for recognizing when a vessel is actively and legitimately engaged in fishing.