sentences:  The roll is an essential for paddlers who attempt serious whitewater (Class IV or greater), as exiting the boat and swimming gives the paddler less maneuverability and control, and thus leaves them more exposed than in the boat.The skill of righting a capsized kayak was devised by the hunter-gatherer societies that also developed the kayak as a hunting boat; the Aleut and Inuit people.The Greenland Inuit used several techniques that allowed the kayak to be righted with or without a paddle, also using only one hand, or without hands at all.