I sail on one of the great lakes, and I've had the exact same thing occur to me, especially when its really blowing, and I'm by myself.
I decided that it's too dangerous to tie myself to the boat, as there's no way I could reel myself in if it was moving at speed. Since I don't sail when it's really cold, I decided the best way was to just to make sure I had the right gear for when it eventually does happen.
So, I got a little dry bag for my iPhone, kind of like this one:http://cascadedesigns.com/sealline/docu ... se/product
It has a vinyl clear window, that lets the touchscreen on the iPhone work without having to remove it from the case. I clip it to a d-hook on my pfd, and fold it into one of the chest-pockets on my pfd.
In my contacts list, I have the mobile contact information for two neighbours who also have cats, and we watch out for each other all the time.
I also take a lesson from my pilot days, and file a "flight plan" with my wife and/or kids.
Just to make sure my system worked, I tried texting and calling home while two miles offshore last summer. Good cellphone reception on the water, because there is nothing to block it. Worked as planned.