INTERNATIONAL ONLY A vessel sounds one short blast. What does this signal indicate about the vessel?

Correct Answer: Option C — The vessel is altering course to starboard

Rule 34(a) specifies that one short blast is the mandatory sound signal used by a power-driven vessel when she is altering her course to starboard. Under International Rules, these signals indicate an action being taken, not a request or intention to pass on a specific side of another vessel.