Question 345 Rules of the Road

The correct answer is C) not required, but may be sounded. When two vessels have reached an agreement by radiotelephone in an inland crossing situation, the use of whistle signals is not required, but may be sounded as a courtesy. The International Regulations for Preventing Collisions at Sea (COLREGS) do not mandate the use of whistle signals in this scenario, as the vessels have already established communication and agreed on their crossing actions. While sounding whistle signals is permitted, it is not a legal requirement in this specific situation. The other options are incorrect because A) requiring whistle signals within one mile is not accurate, and D) requiring them within half a mile contradicts the fact that they are not legally required in this case where communication has been established.