Sit-on-top kayaks are boats with a closed shell which cannot fill with water. Paddlers of this variety of boat therefore needn’t learn to roll, but some sit-on-tops do have leg straps that make it possible to roll. In general, though, rolling a sit-on-top is more difficult than in their sit-in counterparts, due to their higher centre of gravity. The advantage of a sit-on-top kayak is that, if you capsize, you can simply turn the boat over in water, and climb back on. There is a range for various activities from flat water versions suitable for dams, for example, to faster versions that can be used for racing, and those used in whitewater and surf. Others are set up for fishing. For people not keen to roll, a sit-on-top is less intimidating and often more fun than a sit-in kayak, though once someone has developed confidence and competency on a sit-on-top, they often progress to a sit-in variety.