The difference between this beam of water waves and a light beam through a window is in the ratio of wavelength to hole size. This means that two gaps in the harbor barrier make two semicircular wavefronts. Where the circles cross, the wave heights combine by simple linear addition. It is interesting to think of a barrier with many holes. In the limiting case of very many holes, the barrier disappears, being nothing but one gap alongside another.
Semicircular wavefronts combine to make only the incident plane wave.
Hyperbolas do the same. All those waves at nonvertical angles must somehow combine with one another to extinguish all evidence of anything but the plane wave. A Cartesian coordinate system has been superimposed on the ocean surface with x going along the beach and z measuring the distance from shore. The left frame shows the hyperbolic wave arrival time seen at the beach. Frames to the right show arrivals at increasing distances out in the water.