Positive flotation probably wouldn't be offered by manufacturers
voluntarily.
It already is, by several. Sadler & Etap spring to mind.
Goofball_star_dot_etal wrote:
http://www.mikelucasyachting.co.uk/story.htm
Cool link, thanks. Lots of info in there I didn't know
about. I had heard about the sailing-while-flooded test.
There are a couple of people who contribute once in a while
over at the rec.boats.cruising NG with Sadlers.
DSK