🔍 Key Concepts

• Rule 34(d) – Maneuvering and Warning Signals in the Navigation Rules • Purpose of the danger signal (5 or more short and rapid blasts) • Who may use the danger signal when in doubt about the other vessel’s actions or intentions

💭 Think About

• Ask yourself: Is the danger signal limited to vessels that are moving, or can a vessel that is not underway also be in doubt about another vessel’s actions? • Consider whether the rules ever say that only a particular vessel (like the give-way vessel) is allowed to use the danger signal. • Think about the key phrase in the rule: when a vessel is “in doubt” — does that depend on the type of situation (meeting, crossing, anchored) or on the vessel’s state of mind about safety?

✅ Before You Answer

• Verify in Rule 34(d) whether it specifies a particular type of vessel or situation, or simply says “a vessel” that is in doubt. • Check whether there is any restriction in the rule that would prevent an anchored vessel from sounding the danger signal. • Confirm that the danger signal is a warning for doubt or danger, not a routine maneuvering signal limited to crossing or meeting situations.