BOTH INTERNATIONAL & INLAND Which signal shall a vessel towing in fog required to sound?

Correct Answer: Option D — One prolonged and two short blasts every two minutes

Rule 35(c) requires a vessel engaged in towing or pushing another vessel to sound one prolonged blast followed by two short blasts at intervals of not more than two minutes. This signal identifies the vessel as having a tow, distinguishing it from a vessel underway making way.