Could you maybe clarify your question just a bit? Columbus never sailed beyond the Atlantic; all of his voyages of discovery were to the Caribbean at farthest. The Norse had crossed the Atlantic in the 10th century, though they seem not to have explored further south than Newfoundland. Bartholomew Dias actually rounded the Cape of Good Hope in 1488, sailing into the Indian Ocean a few years before Columbus' voyages.
The major skill that the Portuguese navigators possessed (and that Columbus leaned from them) was to take advantage of the prevailing wind and current patterns in the Atlantic to make sailing down the coast of Africa and returning to Europe an easier business. The process involves staring a return voyage by sailing far west, and then turning north and northeast to touch at the Azores and then return to the Portuguese coast.
Edited to add some previous links where I talk about Columbus: