According to Rule 5, what is one of the key responsibilities of a vessel?

Answer: B — Maintaining a proper look-out by sight and hearing

One of the key responsibilities of a vessel, according to Rule 5 of the COLREGs, is to maintain a proper look-out by sight and hearing. This rule emphasizes the importance of vigilance and awareness of the surroundings, which are crucial for preventing collisions and ensuring navigational safety. A proper look-out allows the crew to detect other vessels, navigational hazards, and changes in conditions, enabling them to take appropriate actions to avoid accidents. This rule underscores that effective lookout duties must involve not just visual observation but also listening for sounds from nearby vessels, such as whistles or sirens, which could indicate required actions or alerts. Adhering to this responsibility is foundational for effective seamanship and the overarching goal of maritime safety.