"Driver" and "passenger" side for cars. Oh wait, doesn't work in England etc. I guess for ships there is no variation between countries? Starboard is presumably where the wheel was so everyone must have left it on the right side?
Not the wheel, but (as this article also says) the steering oar. https://en.wikipedia.org/wiki/Steering_oar:
“The steering oar or steering board is an over-sized oar or board, to control the direction of a ship or other watercraft prior to the invention of the rudder.“