Tapered submerged vanes are installed in Wapsipinicon river bend in the USA and outside a new water intake in Nepal. Taper angle is the angle made by leading edge of vane with horizontal in vertical plane. A tapered vane also induces something called the vortex lift (at high angles of attack) which is a secondary lift caused by a reattachment of the flow due to a spanwise leading edge vortex. The aptitude of the vane/ foil to form this leading edge vortex is highly dependent on the shape of the leading edge, generally a sharp leading edge will form a strong vortex whilst a rounded leading edge will form a weaker vortex (with the vortex centre further downstream). In this paper, the effect of taper angle variation within a range 33.7° to 45° on moment of momentum (MOM) has been investigated and it is observed that for a given optimal angle of attack as 40°, MOM can be further increased by keeping the taper angle as 33.7°. © 2007 International Association of Hydraulic Engineering and Research.