True, but you can do most of *that* sailing by coast-hugging - which indeed was more or less the standard for Mediterranean sea travel, far as I know. Not that Atlantic and Baltic sailors didn't mostly rely on that approach too of course.

Doesn't yet speak of ocean-crossing level of shipbuilding and navigational chutzpah, though obviously an even more salient issue is why they'd have sent an expedition into that featureless desert of open water in the first place...

The "blown astray by storm" theory might work, though I've my doubts about period Mediterranean ships' ability to withstand Atlantic storms - and there's also the obvious question of how they'd then get back...