Definitions #

• Swell: sea of wind that has left its generating area
• Wave: sea of local wind
• The fetch is the distance over which the wind acts to create the waves.
• Wave length: distance between two crests of a wave train

Formation #

1. Creation of waves over the entirety of the world’s seas
2. After the wind weakens or the waves spread outside the windy area, they spread freely, which is then called the swell

The height (from trough to crest) of a wave is a statistical height. Example: we take a series of 100 waves. On these 100 waves we keep only the 33 highest (the third). We average the height of these 33 waves and it is the “reference” height. It is sometimes noted H1/3.

Energy of the wave #

When waves do not break, there is almost no horizontal displacement of water over a short space of time. They are waves (energy displacement).

Be careful when the wind and waves are opposite the current. This raises a chop that will quickly become dangerous. When calculating a tide, take waves/swells into account.