Canoes involve the paddler kneeling or sitting in a raised position and using a paddle with one blade. Canoes can be paddled on flatwater or whitewater, though depending on the skill of the paddler, their use may be limited by the open nature of the craft. Due to the single bladed paddle, canoeing can be more difficult to learn than kayaking, yet it offers a unique grace and appeal that has continued to draw people to the sport. Canoes can be used for outings ranging from a few hours to many weeks, and boat styles and designs reflect the intended use. Whitewater canoes are shorter and tend to have more rocker, while tripping canoes are longer, with less rise from end to end. Tripping canoes also have maximum space for storage, allowing the transport of food and gear for extended trips. Whitewater canoes are designed for maximum maneuverability and a higher water line to keep the boat drier while paddling through whitewater rapids. Canoes of both varieties come in solo and tandem models.