-- Last Updated: Nov-04-12 9:55 PM EST --
Nylon deck skirts can often push off with enough force, especially on a plastic boat.
I disagree with one person above. While I favor looser rather than tighter skirts myself because of entrapment concerns - I'd rather be a bit wet than worrying about getting air - things can be quite different on a composite boat with a sharp, narrow rim. They will trap skirts a lot easier than the big rounded coaming edge of a plastic boat, especially if the skirt has a neoprene deck and goes to helpfully try and stretch when you try to push it off.
If you are talking this combination - neo deck skirt with the thin edged and often deep coaming of a composite boat - you should practice grabbing a handful of skirt and getting a side free that way.
One other option with which I have no experience is to see if there is a suspendered skirt that would both work for your needs and has an easy way to release the straps in a pinch. But remember that you need to be able to manage whatever emergency method without being able to see anything, since you could have to do it upside down in dark or swirling wate.