BOTH INTERNATIONAL & INLAND While underway in fog, you hear a short blast, a prolonged blast, and a short blast of a whistle. This signal indicates a __________.

Under Inland Navigation Rules, for the condition where 'While underway in fog, you hear a short blast, a prolonged blast, and a short blast of a whistle. This signal indicates a', the correct requirement is: 'vessel anchored in fog'. This standard ensures clear navigational intent and collision avoidance.