The ocean surface waves experienced by Rich are created by the wind that he is skillfully harnessing to move in the direction he wants, but also by winds that blow hundreds or even thousands of miles away from his location. The sea state (the shape of the sea surface due to waves) depends on the wind speed, the fetch (the distance across the ocean that the wind blows) and the length of time the wind blows. The stronger and longer the wind, the higher the waves it creates. Once the wind stops blowing, waves that have a short wavelength (the distance from one wave peak to the next) will die down quickly, but the waves with longer wavelengths will travel as swell across long distances, perhaps even across entire ocean basins. Other factors such as strong ocean surface currents and the shape of the seafloor in Drake Passage, between Cape Horn and Antarctica, can also make waves higher. So, in fact, it’s quite difficult to predict just how long large surface waves will last, even once the wind falls out of a ship’s sails.
Special thanks to Dr. Tobias Kukulka (University of Delaware) for sharing his expertise on wind waves.
Question asked by Rich, aboard Great American IV