One additional thought
2 Hulls Dave has implied that a monohull that rolls in a bad storm would sink and that would be a rare occasion indeed. Monohulls have often been known to do a 360 degree rollover in outlandish seas and a couple have written survival stories of rolling over twice without sinking. Yes they did get some water inside but not so much, because unless they are extremely broad beamed sleds (which are stable upside down just like a multihull) they are unstable upside down and flip back up quickly. Even more so if they get dismasted. The biggest worry then is getting holed by a mast tethered to the boat. So if you are going offshore, carry a large boltcutter, to cut away your rigging. I do.In the two races most infamous for loss of life, The Fastnet and the Sidney Hobbart, Some boats were found still floating after the storms with companionways open, with no crews on board. Nearly all lives lost were attributed to disastrous attempts to board life rafts. The rafts broke away or flipped crews into the water and blew away so fast that the crews couldn't get to them or get back. Crews who stayed with their boats survived. The lesson here is that the best way to abandon ship is by stepping off the top of the mast as the boat goes down,(which it probably won't).