They didnt have to sail to Africa per say.
By the time of those trips, there had been a reliable trade network for more than 1500 years stretching from Africa up through the Middle East into India.
I don't doubt that it'd be possible to harbour hop those boats down to Africa, but they only needed to go as far as India/Persia to connect.
grue@lemmy.world 6 months ago
Sure, I’m not saying I doubted that part. The part that apparently doesn’t have real evidence and thus seems implausible is the notion that they continued all the way around the Cape of Good Hope and across the Atlantic.