Many modern catamarans incorporate these features already.

Paul Oman wrote:

Seems to me that watertight bulkheads forward of the mast,
aft of the forward cockpit, and watertight floorboards
(lots of stories of water rising up thru the floorboards)
would be life/boat saving design elements.

Most cats have collision bulkheads forward. Mine has 4 watertight
compartments forward, and two aft. Also, with no keel and foam
construction, its virtually unsinkable.


Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

Many cats have this - and with two engines the odds are further improved.



Maybe even a watertight companionway hatch so that the
entire main cabin could become a giant air chamber....


A bit problematical ... a singlehander might want to seal himself in for
the southern ocean, but most folks want easy access to deck.



If not watertight bulkheads, how about inflatable airbags
in the cabin to keep the hull afloat?

This can be done for some boats, but ocean cruisers often chose very
heavy boats, making this difficult to implement. A 6000 pound keel
requires about 100 cubic feet of flotation - that's a 5 foot cube for a
fairly modest boat!



On more unconventional design considerations - bilge keels
would have keep many of the boats I read about from
pounding their topsides to death on reefs or beaches. I
know bilge keels have there faults (I've read about
everything I could find on bilge keel cruisers) but a boat
that reduces draft when not heeled over and sits upright
could be a real life saver.

Again, cats incorporate bilge keels. Many cats have "sacrificial keels"
and will "reduce their draft" from 3 feet to 2 automatically when
passing over a reef!



Even more radical might be a A frame type mast (ie. sold
shrouds, no center mast) would keep the rigging in place
after a roll-over/broach much better then a stick with
wire rigging.

I'm curious - is there any evidence for this?



Anyway, I'm surprised more offshore boats aren't resigned
or retro-fitted for max survival. As I read this book it
made me realize these aren't just boats, often they are a
couple's home for decades (and lost in minutes). Surely a
few watertight bulkheads and watertight/airtight hatches,
while probably a pain to deal with on a day to day basis,
could keep you alive and your home/boat afloat.

Some of the modern cruisers have some of these features. And the long
distance racers have many of them. But, a large number of world
cruisers are using boats built 30 years ago. Most new boats never leave
protected waters, and even the ambitious cruisers usually are actually
island hopping. Statistically, there's a rather small market for this.