Why is the Right of a Ship called Starboard?

Because of the Vikings! The Vikings were famous for their boat and shipbuilding. The ships were usually pointed at each end and wide in the middle. This meant, that they could sail in relatively shallow waters.

At the right side of the ship, near the back, was a large paddle tied to the hull for steering. The Vikings called it styrboard (which means steer side).  The term was adopted into old English as steorbaord, which later became starboard.

With the steering on the right side of the ship, the Vikings docked on the left side and so called it «ladebord» (loading side) which the British turned into larboard. Because starboard and larboard sounded too much alike, the docking side became the port side.