I know about boats that are holes in the water for motors, and I've run for the bulwarks in my skivvies. Lucky for me, I got to stop running before I got to the bulwarks (the wire that was tripping us parted, and we settled down to make coffee and go chase the barge). I also know guys who got out through wheelhouse windows, and I've thought about a jump from the wheelhouse door (Lucky me again, things got better fast). Getting out and off is sometimes enough. Trying to gather equipment/supplied first is probably asking too much time.

I was thinking of something like a water bottle, or even just a ziploc bag, empty except for maybe some iodine or chlorine tablets. It's going to be of use only in some unusual circumstances, but it is something fairly cheap and light that could be of use.

Of course, I never thought of any of this stuff when I was afloat. I had the gumby suit and life jackets accessible and that was about it.