Wakes represent a richly structured example of hydrodynamics at the air/sea interface. Though a common sight in most decent-sized bodies of water, they can reveal a subtle beauty when left to evolve undisturbed. With relative scarcity of marine traffic and long summertime days, the fjords of northern Norway can afford an excellent opportunity for observing wakes in a well-developed and relatively pure state.
In the picture here one may discern an apex angle for the wake envelope of approximately 19.5 degrees, a value first deduced analytically by Lord Kelvin in the late 19th century. This angle is general to all wakes generated by a body traversing deep water, and hence can also be observed behind waterfowl. The defining pattern of a wake is in localized groups of diverging surface waves. The nonlinear physics of the wave localization, which leaves a well-defined region of calm water directly behind the boat (the “narrow-V”), is still an ongoing aspect of research.