Port and Starboard

Port and starboard are used instead of left and right because they give a fixed, unambiguous reference that does not depend on which way a person happens to be facing. Left and right change if you turn around, but the port side of a ship is always the same side, whichever way a crew member is looking, which is essential when orders must be understood instantly and correctly. Facing forward toward the bow, port is on your left hand and starboard on your right.

The words have historical origins that also explain their meaning. Starboard comes from the old "steer-board", the steering oar that early ships carried on their right-hand side before the invention of the central stern rudder. Because that steering oar was on the right, ships came alongside a quay with their other side to avoid damaging it, and that loading side became the "port" side, the side placed against the port. This is a useful way to remember which is which, along with the memory aids that both "port" and "left" have the same number of letters, and that the port navigation light is red, the same short word paired in the mind.

The distinction is built into the rules of the sea. At night a vessel shows a red light on its port side and a green light on its starboard side, so that another ship can tell its heading and aspect and apply the COLREGs correctly in a crossing or head-on situation. Buoyage systems mark channels with port-hand and starboard-hand marks, and helm and lookout reports ("vessel fine on the starboard bow") depend on the shared terms. Every seafarer learns port and starboard from the very start of training, because clear, consistent reference to the two sides of the ship is central to safe navigation and ship handling.