Mike,
Personally don't see how enough foam could be squirelled away in an A/C cruiser to make significant difference. But there's no reason emergency bouyancy bags couldn't be secured inside the boat, placed in a way the inflation of the bags wouldn't hurt or smother an occupant below, and leaving some room to manuever. Maybe the bags could be inflated in a totally swamped situation to void enough water to get the vessel to float on its own again.
[There you'ld be, soaking wet and cold, still alive after the worst night of your life. The bouy bags are keeping the boat afloat at the sheerline, but waves are still washing aboard over the stern into the cockpit. Looking into the companioway there is only water below upto the bridgedeck. You reach in, push a switch and in a series of hisses and whooshes the water below erupts out of the companionway. Instead of water there are tan pillows in the space. Suddenly the boat is floating a foot higher and the raildogs are flopping now but keeping the waves out. You find a snickerdoodle bar in the emergency bag and the sun breaks thru the clouds.]
Check out the site below. Just found it. One comentator described this as 'emerging technology.' The outfit targets small boats and puts the self-inflating airbags down on the spray rail in speed boats. But it certainly is the right idea, my comment being that if the vessels they depict overturn the placement of the bags might float the boat but probably upside down.
Keeping a displacement ocean going sailboat in trouble afloat will require a lot of serious and clever development of a system - but it's an idea that's already here! Nothing new under the sun. I'ld have more faith in the outcome if, instead of this company being in Colorado, they were located in Coronado.
www.goboatingmag.com/main/article.asp?id=3555