The lesson was learned with Titanic, so now all ships have enough life boats, but the reason Titanic didn't have enough (they were ugly and took up space) is still quite valid. Inflatable life rafts aren't nearly durable enough, but if we inflate life boats with a quick curing expanding 2-part expanding foam, they could become sturdy rigid vehicles minutes after inflation. These can be stored inobtrusively, packed into the railings on multiple decks.
These would of course be modern fully enclosed life boats. The door would be made of conventional materials, and actually be part of the railing, so after the boat was fully inflated and cured, the railing could be opened and the passengers could step through it and down the foam-filled stairs into the body of the life-boat. Cranes would fold out of the railing to lower the boat into the water. The section of railing with the boat would break away... Oh, wait, we might want to leave some railing there for the safety of those still loading onto other boats. Minor details...
During the muster drill at the start of each cruise, one boat should be chosen at random to inflate. Some lucky people get to see it in person. The rest get to watch on video monitors. That boat gets lowered into the water and is piloted to shore by the captain before he returns to the ship to cast off. Obviously the ship is equipped with a least one extra so they don't have to replace the test boat before casting off.-- scad mientist, Apr 22 2016 I thought the passengers were supposed to want the captain to die. So, the demo might have a different effect than desired.-- notexactly, Apr 22 2016 'tis good.-- 2 fries shy of a happy meal, Apr 23 2016 I thought initially that this was expanding foam life boots. One needs very good balance to use life boots, or things quickly turn heavyside down.-- bungston, Apr 23 2016 We are fairly sure this is Baked ... will try to find a link.-- 8th of 7, Apr 24 2016 Maybe a few cans of Great Stuff could save the whole ship?-- RayfordSteele, Apr 24 2016 random, halfbakery