This dissertation investigates the mechanisms of ventilation inception on surface-piercing hydrofoils under quasi-static variations of the angle of attack (AoA). Two hydrofoil geometries, a Semi- Ogive profile with a blunt trailing edge and a streamlined NACA 0010-34, were tested in a towing tank across a range of Froude numbers (Fnh) and aspect ratios (AR). The study introduces a novel experimental methodology, quasi-static testing, which eliminates inertial effects associated with acceleration by maintaining constant Fnh while varying AoA. This approach contrasts with traditional ”static tests” found in the literature. A new flow regime map in the α−Fnh parametric space was developed, tracing distinct ventilation inception boundaries for the two hydrofoils and offering a more detailed representation of transitions between flow regimes. The findings challenge the validity of previous methodologies, which assumed that ventilation inception boundaries were dominated by stall angles and fixed AoA, overlooking the dynamics of ventilation inception. At low Fnh, leading-edge (LE) ventilation appears as the dominant mechanism, slightly enhancing lift by stabilizing flow on the suction surface. As Fnh increases, transitions to Rayleigh-Taylor (RT) instabilities become evident, particularly at moderate Reynolds numbers. At high Fnh (≥ 2.5), RT instabilities prevail, with trailing-edge (TE) effects becoming significant for the Semi-Ogive hydrofoil. In contrast, the streamlined NACA 0010-34 primarily exhibits RT-driven mechanisms. The results demonstrate that this new methodology yields precise and repeatable inception boundaries, representing a significant improvement over historical techniques. Notably, contrary to prior assumptions, the AoA at which ventilation inception occurs exceeds 15◦ and is no longer constant across various Fnh. Additionally, trailing-edge geometry was found to influence ventilation inception, particularly at higher AR, as evidenced by the diverging trends observed between the two hydrofoil profiles. Furthermore, the experimental results align well with semi-empirical models for lift and drag coefficients at Fnh ≥ 1.0, reinforcing the robustness of the findings. These contributions provide more in-depth insights into ventilation inception dynamics and offer valuable guidance for the design of hydrofoils in marine applications.