<P> Port and starboard are nautical and aeronautical terms of orientation that deal unambiguously with the structure of vessels and aircraft . Their structures are largely bilaterally symmetrical, meaning they have mirror - image left and right halves if divided long - ways down the middle . </P> <P> To understand which is which, when a person is facing the bow on a vessel or aircraft, that is, forward towards the direction the vehicle is heading when underway, the port side is the left - hand side and the starboard side is the right - hand side . However, port and starboard never change; they are unambiguous references that are not based on the relative directions of an observer, just like the cardinal directions of east and west don't change no matter the direction a person faces . </P> <P> The term starboard derives from the Old English steorbord, meaning the side on which the ship is steered . Before ships had rudders on their centrelines, they were steered with a steering oar at the stern of the ship on the right hand side of the ship, because more people are right - handed . Since the steering oar was on the right side of the boat, it would tie up at the wharf on the other side . Hence the left side was called port . </P>

What is the port side of a boat