OK, I'd like to dance in the twilight zone. It really isn't a big deal for trying to figure out if a boat has plenty of water
tight compartments. If you step down into the hull
and can walk all the way forward to within two feet of the bow, that compartment is going to be too small to keep the boat afloat in the event of a breach amidships. If you don't have a big water
tight chamber aft, then that will just confirm it. As to having "the second hull" and depending upon that to keep the boat afloat, that's ridiculous. If the breach hull
has no structural bouyancy and were to sink down to the deck
the water would be going a good ways onto the bridgedeck. Add a little bit of wave action and it will flood the other hull. Our particular boat has a half height bulkhead coming above the water line (actually pretty far above the water line) going to a large anchor locker
on both sides. It's about 8 ft long 6 ft high and probably on average maybe 2 ft wide so guestimate about 96 cu ft of bouyancy on each side. I'm going to gasket
and seal that door with acorn nuts before doing serious offshore
stuff. The aft section has another maybe 12 ft of bouyancy in the transom. According to Lavranos, should I get a big hole in the boat amidships, the hull would float with the bow in the air and gradually going back to the aft cabin
being lower in the water. Not great, not bad. It would be enough bouyancy that it wouldnt sink sideways. If someone though had a birth up forward, as do MANY cats, that deck
would be completely awash and it probably would sink sideways. If you had something that was 10 thousand of lbs heavier than our boat as many are, then it would need far more captive structural bouyancy. And frankly I just haven't seen many boats that have that. Prout 45s do. Big water tight bulkheads for and aft with huge water tight doors with acorn nuts securing them on gaskets. No penetrations.
Will your cat sink with a mid section breach? Got a birth forward in the hull with no above water level bulkhead seperating it out? Or a forward head
that also goes way up to the bows? Couple that with no large water tight engine
compartment aft (if you noticed the bouyancy for the FP was provided by her aft engine
compartments), and well, probably.
No one should be surprised that certain multis are sinking, especially if they are heavy, and have sacrificed that structural bouyancy for extra accomodations. No need to mention or knock certain boats, it's pretty easy to simply look at the layout and tell.