The image above is of the helm of the beautiful Star of India. Based out of San Diego, Star of India is the oldest working merchant vessel in the world and she is a piece of living, breathing history. If you've ever seen the "Tar Rigger" episode of Dirty Jobs, you've seen the Star of India. You've also witnessed just a little bit of how hard sailors work to keep up their ships. Especially sailing ships like the one in question.
But back to the helm. On any vessel the helm is simply the mechanism by which the ship or boat is steered. On small boats such as gigs and pinnaces, the helm would consist of a simple tiller attached directly to the rudder. This may also be the case in a smaller sloop or schooner - the kind pirates loved so much. In larger ships, again sometimes schooners and certainly frigate class ships and men-of-war, a wheel did the work. The wheel would control the rudder in such cases through a system of braces, gears and ropes.
The helmsman would be, of course, the man at the tiller or wheel. Orders to the helm indicated which way to move the tiller. As an example, the order "hard to starboard" would require and opposite reaction from the helmsman. The tiller being moved toward larboard (modern day port) would make the vessel turn to starboard. Certainly a confusing situation for anyone who lacked experience and only the most trusted and seaworthy men were given the job of helmsman. Then too there was the whole starboard/larboard thing which could get a little mixed up in anybody's head now and again. Particularly after your grog ration. Better add sobriety to the list of your helmsman's virtues, mate.
Try to keep that in your head as you go about your business today. There was a lot a "simple" sailor had to know, not the least of which was how to keep his wooden world on tack and afloat. And if you're ever in San Diego stop by for a tour of Star of India. She'll take your breath away, I promise. And give you just a hint of what life on the waves used to be like.