Egyptians in the New World?

[Sean Manning]

I'm saying that as far as we know, roundships in the Mediterranean often sailed by the shortest route rather than the one that kept them closest to shore. The Rome to Egypt grain route is another good example (the great grain ships only put in at a Greek port if the weather forced them to). You would have to do your own research on voyages on the Atlantic to decide what would be plausible. A story where one merchant ship ended up in Brazil or the Carribean wouldn't strain my credulity at all ... five hundred years is a enough time for several unlikely things to happen together.

Edit: Without looking at a map and a wind and current chart, I can't think of a strong reason for a fleet off Mauritania to sail far from shore. I just don't think that Greek and Roman sailors were terrified of open water.