This is a Soviet movie version of Jules Verne's "Un Capitaine de quinze ans" (A Captain of Fifteen Years)
Junga Dick Sands takes the place of the deceased captain and drives the ship "Pilgrim" to Africa, not America, while the vile slave trader Negoro has placed an ax under the compass.
So the fifteen-year-old captain, the shipowner's wife with her grandson, the teacher and the crew were captured by bad guys who treat people like a commodity.
