An officer of the deck (OOD) underway is a watchstanding duty officer on a surface ship in the United States Navy, United States Coast Guard, and NOAA Commissioned Officer Corps who is tasked with certain duties and responsibilities for the ship. The officer of the deck is either subordinate to the command duty officer or, in the absence of one, reports directly to the ship's commanding officer and executive officer, in the latter case holding responsibility for the ship altogether. This article describes duties and responsibilities for an underway OOD for surface ships only.