Kayak rudders are usually included on touring kayaks, and are used to help keep the boat on track during rough waters. The rudder can be used for steering purposes as well, and when not in use, can be pulled out of the water and mounted on the deck of the boat. The function of kayak rudders does not vary much, though the shape of the rudder can change according to the manufacturer's specifications. The manner by which the rudder is raised from or lowered into the water can vary as well.
Operating the rudder involves using a rope mounted in the cockpit of the kayak; this rope allows the paddler to lower the rudder into the water or raise it out of the water. Kayak rudders are turned using foot pedals inside the cockpit. Pressing on one pedal turns the rudder in one direction, and pressing the other pedal turns the rudder in a different direction. These pedals are sometimes used in lieu of fixed foot pedals mounted in the cockpit, though other types of kayak rudders, such as the Smart Track rudder system, uses both fixed foot posts and moving foot pedals to ensure the paddler has a solid place to rest his or her feet when bracing during maneuvering.
It is possible and sometimes not very difficult to make a kayak rudder from scratch rather than buying a prefabricated model. The rudder will need to be made from a durable material that is not susceptible to water damage; plastic is the best choice, though a high grade of plastic will be necessary. The ropes and pedals can also be made custom to work with a specific kayak. The process of making such a rudder is not exceptionally difficult, but the builder will need to take special care to avoid permanently damaging the boat.
A relatively new type of rudder is made of carbon fiber. This design uses lightweight rigid carbon fiber to form the rudder shape. This is advantageous because it saves on the overall weight of the boat, and it will be less susceptible to damage should the rudder collide with a hard object such as a rock or log. These kayak rudders are much more expensive than plastic rudders, though they are likely to last a long time. Metal rudders are also available, though they are less common than plastic because metal tends to be heavy and susceptible to damage from moisture.