I am not even talking about that much.

There is nowhere in the oceans of Earth that is 5,000 miles away from land. The furthest any point in the ocean is from and is 1,000 miles, and the deepest part of the ocean seems to be only 6.8 miles. 

The diameter of the Earth itself is less than 8,000 miles. The circumference is 24,901 miles, but there are so many land masses spread across the surface that it breaks up the oceans too much to allow for 5,000 miles from land at any point.