Just make sure it`s only air you have inside.
Many years ago a Paper-tiger owner filled his boat with those inflatable bags that came from box-wine (if you don`t know what I`m talking about, they are 5litre plastic bags with a silver foil-type outer surface & a type of tap, like a strong plastic bag mated with a beer-keg.)

A couple of weeks of standing in the sun, the leftover wine in the bags started fermenting nicely, the strong plastic bage started expanding slowly, until the owner came back to the yacht club, only to find his boat had exploded.

Cheers
Steve