Ummmm...how does this work? Im pretty sure the ghana empire was land locked and nearly 500miles away from the ocean.
Every map we have of Ancient Ghana was drawn by Arabs, there are no surviving maps of their empire drawn by them, if one ever existed.
What empire was standing between them and the Atlantic that could stop them from making the trip to the ocean?
They had the lumber for ship building, the man power to pull off expeditions and the finances to make it happen.
Not to mention all the very large rivers and lakes throughout Africa.