First of all you have to understand that if you don't have a rudder in you kayak, still you need not worry. The rudder is far from being any essential piece of the kayak. However if you still decide to want one then you can add one later. Rudder is placed on the side of the kayak. When you want to lower it then you have to pull the chord to move it down from its stored position. You have to control the rudder with foot pedals. The main purpose of the rudder in a kayak is not to turn a kayak. It is to keep the kayak straight in the water when you are paddling in wind. The kayak tends to turn into the wind known as 'weather chocking'. If you don‚Äôt have a rudder then you have to take extra efforts to paddle on one side to keep the kayak straight. This happens because the water is hitting the kayak from both sides at the front and pinning it. However past the middle portion of the kayak the water is not hitting your kayak making a low pressure zone at the back. Now if there is strong wind then your stern will be blow along with the wind. And that shall cause the kayak to turn into the wind. This can be checked by a rudder. When you drop it then it helps to keep the stern in place. You can adjust control of rudder from your foot to adjust for meeting different conditions of wind directions. Also it helps you in turning. Therefore you need a rudder for kayak. That‚Äôs it.