This paper reports on studies on the augmentation of ionic mass transfer rates due to the presence of insert promoters-coaxially placed helical tapes on a rod-in a forced convection flow of electrolyte. The experimental limiting current data were obtained at various flow rates using promoters of varying central rod diameter width and pitch of the helical tape. Altogether, 1200 experimental limiting current measurements were obtained covering a wide range of variables. The data are analysed and results are discussed in detail. The developed correlations based on experimental data are presented.