What is the purpose of a jib (head sail) on a sailboat?

Question

I am currently learning how to sail while simultaneously learning how to teach others how to sail. (Rather weird I know). I know how to use the jib but I’m not quite sure its purpose. Can someone please give me some insight on this matter?

Answer 1

The purpose of any sail is to harness the energy of wind to provide the power to propel the boat through the water.  Not all sailboats have jib sails.  A boat that is designed with a main and a jib performs best when both sails are used and properly trimmed.  The boat is in balance when the center of effort is aligned with the center of lateral resistance.

You can also use your sail trim to assist in steering the sailboat.  To fall off, turn away from the wind, keep your jib trimmed while letting out the main sail and pulling the tiller away from the main.  In a stiff breeze, this will really help when rounding the windward mark to make for the next mark directly down wind.

Answer 2

Like any sail, it can be let out when going down wind (running or broad reach) and will create more surface area for the wind to push.  Heading up wind, when properly trimmed it will make foil, just like the mainsail.  The difference in pressure pulls the boat forward.

In addition the jib or other headsail funnels more wind over the mainsail when heading to windward which increases the foil effect of the main.