People on life rafts have to collect rainwater, and also can derive
significant fluids from eating fish (if they can catch any). Also,
life rafts often carry an inflatable "solar still" which looks like a
beach ball floating in the ocean and distills fresh water from sea.
More recently, life rafts have taken to carrying reverse osmosis
filters which rely on hand pumping to provide pressure (this is what
we had when I worked on the Shell Venture).
Drinking sea water causes the body to excrete more fluids, making
things worse than not drinking at all. I don't know about "crazy",
but I have seen people who have accidentally become severely
dehydrated and they definately start losing touch with reality.
Also, I can well imagine going crazy trying *not* to drink the sea
water after a day or two without fluids.
steve