Your pants can be used for more things than just holding your wallet and keys. Your pants can actually help save your life in a water survival scenario.
Lets use a scenario where you are out boating several miles from shore and for some unforeseeable reason the boat sinks. The boat owner did not have life jackets or any other flotation devices on board. Hopefully, you are not the boat owner that made that costly mistake.
Now, the boat is nowhere in sight because it is now at the bottom of the lake. You are alone and hopefully have some type of swimming skills, especially on how to tread water. If you can not swim, I would suggest learning now before you need the ability to do so. If you can't swim or tread water, this technique will not work for you.
If you are wearing shoes, attempt to remove at least one show string and discard your shoes. This will remove some wait that will drag you down. Hold the shoe string in your mouth until needed for the next steps. If you are able to tie the bottom of the pant legs together into a knot, then you may not need the shoe strings. It depends on how thick your pant material is and the pant size. The larger the pants, the more difficult to tie. I know from experience.
Remove your belt if you have one. Remove any heavy objects from the pockets like keys, etc.
While doing these steps, it is important not to panic. You may need to go under water once in awhile to do some of these steps to relieve some pressure from treading water. Just hold your breath, sink a little, do a step, and then come back up for air. The colder the water, the harder it is to do these steps.
After removing the belt and other items, if you are able to slip your pants off without undoing the snap and zipper then do so. If not, you will have to close the snap and zipper after removing your pants.
Once the pants are off and everything is snapped up, you will need to tie the pant legs together at the cuff so that air will not escape through them. If you are able to tie the legs together into a knot without using the string, then do that. If it is difficult, then use the shoe string. I prefer to use the shoe string because I can tie the pant leg opening closer to the ends so that it will hold more air.
Next, will need to place your head between the opening of the pant legs with the cuff facing to your back and the zipper facing down into the water. You should be looking at your rear pant pockets if done correctly.
Next, bring the opening up above your head and the scoop downward toward the water trapping air into the pant legs. You need to squeeze the belt opening together at chest level so that air does not escape back out. You will need to do this step as needed to keep air in the legs. You can also slightly open the belt area up and slap water and air into the opening and then close it back up.
Next, after the pant legs are puffed up with air, lean back slightly while keeping the belt opening closed at the chest with your arms. Determine where the nearest landfall is and start pedaling with your feet toward that direction. You will be traveling backwards, so every now and then look back to make sure your are not heading for any type of hazard or danger.
There is an alteration to this technique. You can tie off each pant leg individually resulting in two floating ends. You keep the belt opening down into the water and place your chest between the crotch area and you can pedal forward on your chest rather than on your back.
Note: If your pants have holes in the knees or crotch area, this technique will not work.
Stay Prepared! Stay Alive!