why are the sides of a ship called port and starboard
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 and, because more people are right-handed, on the right-hand side of it. 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.