The spray skirt or similar waterproof garment attaches securely to the edges of the cockpit , so that no water from waves or spray may enter the boat . Therefore in most styles the boat can roll upright again without it filling with water or ejecting the paddler . The spraydeck or similar waterproof covering attaches securely to the edges of the cockpit , preventing the entry of water from waves or spray , and making it possible , in some boats , to roll the kayak , capsizing and righting the boat without it filling with water or ejecting the passenger .