Ok, I just remembered one day I was sailing and I had this idea. I kind of forgot about it until 30 seconds ago.

I was thinking of a canister mounted on the rear beam with coiled stretchy and floating line in it. In the middle of the line there is a sea anchor. The rest of the line is feed through the sea anchor hole and is attached to an end cap for the canister. You are attached to the end cap by some line (with a quick release) as you fall off the canister opens pulling out some line then the sea anchor then some more line.

What do you guys think?

We are looking at small amounts of money and 2 holes in the beam

Again my boat rounds up very quickly up or down so I am not as afraid as most of you of being dragged for an extended period.

Matt