I was very happy with this story and enjoyed it quite a bit - the idea of a person who, deep down had always longed to be at sea and was drawn to it through everything he did - then found himself a "fish out of water" in a dead-end job, away from what he loved, in a situation he couldn't control and didn't speak to his essential nature. When the opportunity came up, he would have had no choice not to take the job - his rationalizing about the money for a family was just his way of making excuses for it, because I think deep down, he didn't consider himself to be human at all, and after being discharged, was simply going through all the motions of what one would expect a person to do. It's no surprise that - what with the communication issues (text-only) and completely different environment, he finally abandoned his connections to humanity completely and swam off to fulfill his quest for self. I think it raised interesting questions about who we are at heart, who we want to be, and the sacrifices we make as we try and understand how to reconcile dreams and reality.
The best part of this story was the Jonathan Coulton song at the end. I've bought it now, and thought it fit the story perfectly. Nice find, Steve!