I won't say impossible, but I think it is not very likely. Roman ships weren't really designed well to handle on the open expanses of the Atlantic, far from shores, dealing with its storms and currents, were they? The Romans knew of the Canary Islands, and though there are signs of prehistoric human presence on the Azores, I don't think the Romans knew of them, nor any modern Europeans, till the Portuguese discovered them.
Prost!
Brad