After sailing from Africa, it took between 35 days and 4 months for ships to reach their destination.
The period largely depended on the number of stops and the destination. For instance, it could take about 35 days for ships to arrive in Brazil from Angola and 3 months for vessels leaving West Africa for Europe.
It typically took more extended periods for ships sailing from Southern Africa to reach their destinations. Trips were made longer on account of weather and number of stops at ports to offload goods on rare occasions.
Ships took commodities and livestock in addition to a few numbers of captured Africans, but at the turn of the 16th century, when slavery became a huge trade, ships were specially designated to carry Africans into bondage.
Many captains of ships, slave masters and surgeons on board were made to sign agreements to treat the Africans on board the ships well. Ships were often checked to ensure the safety of the Africans but the signed documents and checks did nothing.