To produce a shock wave, an object in a given medium (such as air or water) must travel faster than the local speed of sound. In the case of an aircraft that travels at a high subsonic speed, the surrounding regions of air can travel at exactly the speed of sound, so that sound waves leaving the aircraft accumulate on top of each other, similar to a traffic jam on a highway. When a shock wave forms, local atmospheric pressure increases and then spreads sideways. Because of this amplification effect, a shock wave can be very intense, more like an explosion when heard from a distance (not by chance, since explosions create shock waves).
The ship moves faster than the speed of the waves in the water, so the waves have to get out of the way. The sound you hear when you break a whip is the result of weak shock waves produced by the tip, which moves quickly. In physics, a shock wave (also called a shock wave) is a type of disturbance that propagates and moves faster than the local speed of sound in the medium.