These two (which are not sisters in the strict sense, though they may work together):
AUBACORA: FN-1537-N, call-sign CUSF2
318gt 33.29/38.98m 692kW
built 1981 unknown, Portugal
LIBERTAS: FN-1506-N, call-sign CUSG4
263gt 30.03/34.25m 625kW
built 1985 unknown, Portugal
I wonder whether the South African reference is due to confusion with another AUBACORA?
IMO 8131300
292gt 32.87/37.01m 748kW
built 1981 Omelas Fishing Co (Pty) Ltd, Cape Town for own account as AUBACORA
1983 ren ALLELUIA
2002 Marco Fishing (Pty) Ltd, L