A GaleSail is a storm jib made by ATN designed to be deployed over a roller up furlingjib.
I bought one about three years ago and set it one time just to know how to do it.
Have not yet used it in a blow. I have luckily managed to stay out of sustained winds greater than 35kts.
Like my liferaft and EPIRB, I hope I never really need to use it!
just went back to a practical sailor copy june 2009, and there was an article comparing the atn gale sail to the storm bag sail. the mag liked the gale sail better, but prefered both a solent stay, and best, an inner forestay, to the gale sail. got to think about all this...