The influence of the cavitation level on the vortex shedding frequency is used to compare the flow field in the wake of a blunt hydrofoil, with and without hydroelastic lock-in, and with a constant Reynolds number. Accurate LOA measurements allow us to examine in detail the base flow regime considered as the excitation source of the hydroelastic phenomena. Thanks to these measurements, a second vortex street superposed on the Karman street has been observed. Comparisons between measurements and calculations show that a Strouhal number evaluation based on boundary layer displacement thickness agrees well with experiments. Finally, the influence on the configuration of the wake is considered by modifying the shape of the trailing edge.