15 nautical miles is about 17 regular miles, so it might make you wonder whether it would have made more sense to try to swim to shore. Treading water is less exerting, but maybe no one will ever come. Imagine hour after hour just staying in one place off shore!
Here, I found an article on the subject:
What if it’s two miles to the beach? Three? Sometimes, I feel like it might as well be 10,000 miles, but I know for sure, that waiting for a boat to happen by, is as likely as me winning the Power Ball. I know that I can’t waste one calorie of energy, or allow one thought to set up shop, that keeps me treading water and waiting for rescue....Oh, no! It's just a damned metaphor!
Here’s the take away: The boat may, or mostly likely NOT, be coming, so head for shore and just keep swimming. The status quo of your life is merely treading water. Don’t delude yourself into thinking you are headed to shore, when you have no plan, no written personal vision, no set goal, no direction, no definitive action….you are simply treading water. Ask yourself, “How long can I tread water before I’m exhausted and am swallowed up by the deep?”