INLAND ONLY Two power driven vessels are meeting on a clear day and will pass less than half a mile apart. In this situation whistle signals __________.

Correct Answer: Option D — must be exchanged if passing agreements have not been made by radio

Inland Rule 34(a) requires power-driven vessels in sight of one another and meeting within half a mile to exchange whistle signals unless a passing agreement has already been established via VHF radiotelephone, avoiding acoustic signals when radio contact suffices.