Life Preservers

Underneath the seemingly endless rows of yellow and blue fiber glass seating that lines the interior of the Staten Island Ferry are these words neatly stenciled in white letters: LIFE PRESERVERS. For every six seats, there seem to be four large, pull-down compartments, each ostensibly holding some sort of flotation device.

"I guess that's enough," I said to myself, "even if disaster struck and the boat was loaded with tourists."

But then I added to myself, "what if some of those compartments were empty? Would there be enough then?"

On impulse, I pulled on the handle of the compartment just below me. Nothing. The compartment was bare. I pulled down another. Just empty space. Still another. Bingo! A large orange life preserver glared back at me. It looked worn and very heavy, as though it could just as easily drown you as save you. But surely it could do the job in a pinch.

But what if my random openings indicated a larger pattern that only one in three of all the compartments contained this essential item? I did a quick calculation. Suppose this were the case. Then there might be as few as 2 life preservers available for every 6 seats. Or, if 500 people happened to be on board (a fairly large number) a boat with a capacity of, say, a 1000, there would be only enough life preservers for about two thirds of the passengers. The others would have to fend for themselves. Which means that about 150 people would have to get by on their own. Can that many people, on average, swim well enough to survive?

I am not a particularly good swimmer myself, probably slightly below average, but I'm pretty sure I could swim, say, the half mile to mile that would be needed to get to safety. Using a rough estimate, then, in a population of 500 people with a normal distribution of swimming ability, about 350 can swim about as well or better than I can. Which means 150 people on that boat definitely need those life preservers, which further means there are just enough preservers for those who really need them. Oh, I'm so glad that the New York City Department of Transportation has this all worked out. Now I feel so much better!