BOTH INTERNATIONAL & INLAND A man aboard a vessel, signaling by raising and lowering his outstretched arms to each side, is indicating __________.

Under Inland Navigation Rules, for the condition where 'A man aboard a vessel, signaling by raising and lowering his outstretched arms to each side, is indicating', the correct requirement is: 'a distress signal'. This standard ensures clear navigational intent and collision avoidance.