In Mansa Musa’s own words concerning his predecessor’s reaction to the return of one ship of two hundred;
“He ordered two thousand boats to be equipped for him and for his men, and one thousand more for water and victuals. Then he conferred on me the regency during his absence, and departed with his men on the ocean trip, never to return nor to give a sign of life.”
This is over 100 years before Columbus sailed from Europe.
These true events are largely unknown.
The concept that Africans in the 1300s were technologically advanced, had such ambitions, is not promulgated.