According to the supersport.com website, Zwarts held the rare distinction of never winning or losing a professional fight on points. He won eight of his 16 bouts inside the distance, drew two and was stopped in the other six.
Francois Cornelius Zwarts, who was born in Brakpan east of Johannesburg on November 27 1939, died last Sunday. He had been ill for a long time.
As an amateur, Zwarts won the welterweight title at the 1964 SA Games after also winning a Transvaal junior title.
After turning professional, he was trained by the well-known Cyril Carroll, but never reached great heights. In his first professional bout, at the Johannesburg City Hall on August 16 1965, he drew over four rounds against Japie Smit.
He won his next three fights inside the distance but was then stopped in the eighth round by a future SA welterweight champion, Patrick Toweel, in a clash for the vacant Transvaal welterweight title.
In a return match in April 1968, Toweel stopped him in the second round.
Zwarts beat Tickey Azor, Brian Watson, Pat Breedt, Boet de Bruyn, Jokkie Eli and Bennie Nieuwenhuizen, who was well past his best by then.
He also lost to Pierre Fourie in a bout for the Transvaal middleweight title, to Coert Fourie and twice to Spider Kelly.
He died in Van Dyk Park, Boksburg.