A broad frequency-response peak.
That point in the take-off run at which a seaplane passes from displacement lift to hydrodynamic lift. It represents the process of climbing, by means of the "step" in the floats or the hull and with the help of increasing speed, out of the water on to its surface.
The hump or peak formed on the graph of resistance against speed for planing craft, hydrofoils, or ACVs due primarily to maximum wave-making drag of the hull and induced drag of the foils.