Boating has many origins and the location of the helm is based on both ancient customs and practical reasons. Steering on the (starboard) right-hand side is probably as old as boating itself.
The steering oar or rudder was on the right side of boats long before the invention of engines and propellers and the earliest boats were propelled and steered by paddles. Right-handed paddlers would naturally steer from the right-hand side of the boat. Since the majority of people are right handed so steering on the right was more natural.
The International Collision Regulations also tell us to give way to starboard so sitting on the starboard side lets us see vessels we need to give way to sooner.
According to the United Kingdom’s National Maritime Museum, as larger boats developed, the paddle was gradually replaced by a large oar permanently attached to the right side. Anglo-Saxon sailors called this device the “steorboard” which gradually became “starboard”. The steering apparatus is sometimes placed in the centre of the vessel but the term “starboard” remained the name for the vessel’s right-hand side.
Today the left-hand side of a vessel is called “port”. However, in the early Middle Ages, Anglo-Saxon sailors used the term “baecbord” which may have come from the fact that the sailor steering the vessel had his back to the left-hand side. In later times, sailors used the term “larboard” which may have been derived from “ladderboard”, meaning the left-hand side of the ship where passengers and cargo were loaded (‘laded’). In the 19th century, “port” was adopted as the term for the left-hand side because of confusion caused by the similar sounding words “starboard” and “larboard”. Port also was the side you used to go ashore or into Port.