BOTH INTERNATIONAL & INLAND If you saw flames aboard a vessel but could see the vessel was not on fire, you would know that the __________.

Correct Answer: Option D — vessel required immediate assistance

Under Inland Navigation Rules, for the condition where 'If you saw flames aboard a vessel but could see the vessel was not on fire, you would know that the', the correct requirement is: 'vessel required immediate assistance'. This standard ensures clear navigational intent and collision avoidance.