Kayaks are a popular way to enjoy the great outdoors. They are both light and sturdy, and come in a variety of shapes and sizes. Different styles of kayaks cater to different needs, from novices to advanced users. The material used to construct whitewater kayaks usually has a semi-rigid construction, such as polyethylene. This type of material is lightweight and allows the boat to bounce off rocks without leaking. However, these materials can trap the paddler and accumulate deep scratches.