Q When did my ancestor arrive in South Africa and on which ship?
A Passenger lists are not a good starting point. Organized emigration schemes are well-documented but if your ancestor paid his own passage as an independent traveller his arrival may remain invisible. Registers which have survived are not all-inclusive and are rarely indexed; steerage passengers are seldom named. It’s impossible to speak in terms of a national database of SA passenger arrivals or departures: no such source exists. Very few passenger lists are available online: someone has had to transcribe these from original registers held in archival repositories or from newspaper shipping columns. Those transcribed or otherwise captured so far remain the tip of the iceberg.
British Board of Trade records are available online from 1890 via findmypast and other sites. These may be helpful if your ancestor's surname was unusual, for example, enabling you to identify him or her on a passenger list. If his name was John Smith you will have some difficulty. Some approximate idea of a date of departure or port of destination is useful. By far the largest preponderance of names were going to US rather than to SA. A recent search for an Irish lady turned up hundreds of examples of her names - forename and surname - but only two of these were going to South Africa, the rest to US ports.
Rather than pinning your hopes on finding your forebear on a passenger list, focus on whether he eventually died in SA. If you fail to find a relevant deceased estate file, look for any other likely reference on the index: a divorce, an application for employment or even a mortgage bond. Be imaginative in your search terms.
Emigrants boarding steamer