It doesn't work like that, you might (emphasis on might) be able to pick up some wifi if you are docked, but the farther away you get, the more the signal drops out. The most increase you may get is a extra couple hundred feet at most (and that's being optimistic). Sorry, but what you are asking for is virtually impossible. Just do some google searches for wifi antenna boosters and see what is offered. That is about as good as it will get.
A business / consumer wireless network generally does not extend beyond 25 meters and that assumes no walls blocking the signal. A telecomm's (AT&T, Sprint, Verizon) cell tower in general has a range of 1 to 5 miles. That depends on the terrain, wattage, and the exact specs of the equipment used. Under the best conditions if Verizon were to put a cell tower at the edge of the shore (a really, really, really stupid idea to say the very least), then you can potentially receive a signal 5 miles away from land.
You, my friend, are going to need a remote satellite internet connection. Sounds expensive? Well, that's because it is...
google this video it is called 1 man 1 jar, its a very cool invention this man made and it should help you solve your problem. Other than that all i can say is buy yourself some internet.
Excellent suggestion! I'd forgotten about that guy and his offbeat contraption but you're right, it's a perfect fit for this fellow's conundrum. It's a good reminder, too, of the value of exuberant, fearless experimentation in finding breakthroughs that defy conventional theories. Thanks!