Fun fact about those ships (Mercy and Comfort), the watertight compartments from bow to stern aren't connected until you are well above the waterline. That is, unlike warships that have compartments interconnected by watertight doors that allow you to walk for and aft on several decks, you can't walk bow to stern on Comfort unless you are well above the waterline. When you walk from the brow (there's a door down low and close to the bow) to one of the medical spaces, or, say, to a berthing compartment mid or aft, you first have to climb up several flights of stairs, walk aft over a few not-so-watertight "buckets" to your ladderwell, and then descend. You can take one of the medical elevators down instead if that's where you're going.USNS Mercy (T-AH-19), one of two massive hospital ships of the US Navy. It, along with the Comfort, are the converted San-Clemente class oil tankers (formerly SS Worth and SS Rose City). (The Navy has also had good success converting the Alaska class supertankers to the Expeditionary Support Base ships just coming out, the first of which pictured earlier in the thread, the USS Lewis B. Puller) The hospital ships have full medical services to include 12 operating rooms and 1,000+ beds.
In a naval architecture sense, I always thought those buckets made them a bit like the Titanic.
Incidentally, all those stairs between the brow and berthing are a lot of fun when you mix in alcohol and horseplay... obviously...