Years ago when my sons were working on their Boy Scout merit badges, one of the requirements was to use a pair of pants as a Personal Flotation Device (PFD). The legs were tied off at the bottoms and the top waist area would be held open to scoop air into the pants. The waist would be held closed to contain the air and the pant legs would be positioned over the head with the tied legs behind the neck.
I have tried it and it actually works! But, I like the prospect of something more stable/reliable for floatation so I began to ponder how this method could be improved. In a previous article, “Gallons Of Flotation” I discuss that a gallon of water weighs about 8 pounds, and conversely, a gallon container of air can support eight pounds of flotation. This gave me an idea that empty containers could be used to fill the pants legs to provide reliable flotation if needed. In fact, empty 2 liter soda bottles would fit nicely down the pant legs for this purpose.
I tied the bottoms of the pant legs together then inserted 2 bottles in each leg resulting in a total of 4 bottles that equated to almost 17 pounds of flotation. Then I tightened the belt to close the waist area. I slipped the pant legs over my head with the tied end behind my neck while I used the remaining belt strap to wrap around my leg to secure the improvised PFD to my body. As I entered the water I was glad to have the strap around my leg as it helped to support my body as I floated on my back and freed my hands to paddle in any direction as needed.
When improvising a PDF, any buoyant material could be used as a filler to any clothing, tarp, net, or other surrounding material.