There is one fairly well known story to this effect, involving a 14th century ruler of Mali. While there's always more to say, this question, and variants on it, come up here fairly frequently, and so there are a couple of earlier responses that might interest you while you wait for fresh answers to your query. Try

Abu Bakr II set sail on a expedition from Mali. Is there any evidence of what happened to his fleet?, with u/Commustar

Mansa Musa's father, Abu Bakr II, abdicated the throne of Mali because he was convinced he could find the edge of the Atlantic ocean. What contemporary knowledge fed this belief? Did he expect to find a 'new world'?, led by u/MansaMontezuma