The reason Palos was chosen was an economical one.

The port, for some misdemeanour, had lately been condemned to provide two caravels for the service of the Crown for a period of twelve months; and in the impoverished state of the royal exchequer this free service came in very usefully in fitting out the expedition of discovery.

Columbus was quite satisfied, since he had such good friends at Palos; and he immediately set about choosing the ships.
This, however, did not prove to be quite such a straightforward business as might have been expected.

The truth is that, whatever a few monks and physicians may have thought of it, the proposed expedition terrified the ordinary seafaring population of Palos.

It was thought to be the wildest and maddest scheme that any one had ever heard of.