What scientifically would make it possible that certain large bodies of water be impassable?

What scientifically would make it possible that certain large bodies of water be impassable while others that seem very similar are able to be navigated?

This is not what I am attempting to do, but as an example say in some sort of alternate history no one discovered the Americas due simply to the fact that their vessels could not cross the Pacific or Atlantic Oceans. There were ships that could cross the Indian Ocean perhaps, but not the two that surround the 2 western continents. This would obviously be made possible by further future development, but say until the 1700s it was not.

Is this at all possible? I'm not looking for an answer that they didn't know the continents were there, but rather there is no way they could have known because navigation across those two bodies of water was impossible once a certain distance from Europe, Africa, or Asia was reached.

posted almost 8 years ago

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