Spain was fourth on Columbus' list for potential financiers for his first voyage. England, France and Portugal already had turned him down because they knew he had miscalculated and the voyage would take much longer than he was anticipating.
Not only had Columbus misunderestimated earth's circumference, he had bought Marco Polo's story hook, line and sinker. Polo exaggerated the expanse of China so as to make his voyages sound all the more remarkable. Take the two errors in combination and Columbus was expecting to find the easternmost edge of Asia about 7000 miles further to the east than it actually is.
The range of all sailing vessels is determined by how long the food and water will hold out. All of Columbus' ships were substantially smaller than the Pilgrim's Mayflower. I can't find a reference confirming this but I'd once read the range of a Spanish caravel was about 3500 miles. Which meant exploratory voyages usually sailed out about 1750 miles and then turned back. Except from the Azores to San Salvador, Bahamas is more than 3000 miles.
There's a story that Columbus was awake in his bunk, weighing the decision to turn back just as they sighted land. What's not clear is whether they might already have sailed too far and had too little provisions on board to get back to the Azores.
A lot of crew routinely died from scurvy and such under best of conditions, so it's a certainly a substantial portion of them would have died trying to get back to the Azores. And without fair winds and good luck, it's entirely possible they all would have perished and we never would have heard the name "Cristoforo Corombo."
Which is why I long have considered Columbus to be the luckiest explorer who ever lived. Because I don't know of another whose life was saved by discovering an unknown continent.
But I also think Columbus had to have been one of history's greatest salesmen. It's a certainty he was a smooth-talking son-of-a-gun, else the crew would have slit his throat and tossed his body into the sea long before they'd got to 3000 miles, turned around, sailed back to Spain and told Ferdinand and Isabela their captain was taken by the bloody flux.
I would give that title to the Polynesians who discovered Hawaii since Hawaii is the most remote (now) inhabited place on earth. They managed to do it in canoes no less.
I've often thought that those must have been really wide canoes because they would have to be in order to hold their gigantic balls.