You have it...
Look at the SS from another thread on down I posted, I think it was post 17, but you'll see it. See the blue water in the boxes that have the name of each of compartment. These 3 are totally flooded due to unrepairable bulkheads. If you watch them when you take damage you can see the water rise from the bottom. If you pump it out they will clear. Read more on the thread,
http://www.subsim.com/radioroom/showthread.php?t=153694