The military and boy scouts teach how to make a water flotation system out of the clothes on your back. If the worst should happen and you're in the water with a long way to go, first don't panic. I have done this with pants, shorts, and even a t-shirt. What you'll do is tie the bottom of the pant legs together with a tight knot. Inflate with you mouth and close the opposite end. They're are lot of videos on the tube that show examples.