BOTH INTERNATIONAL & INLAND A fog signal of one prolonged blast followed by four short blasts would mean the presence of which vessel?

Correct Answer: Option D — A pilot vessel engaged on pilotage duty

Rule 35(i) of the COLREGS and Inland Rules mandates that a pilot vessel engaged on pilotage duty shall sound four short blasts in addition to the signals prescribed for power-driven vessels. This unique identity signal allows other vessels to identify the pilot boat's specific operational status in restricted visibility.