The Waves of the Sea: Types, Origins, and Secrets of Navigation

Marine waves are classified into different types based on their origin, formation method, and behavior. Here are the main types of waves and what they indicate:

1. Wind Waves
   • Origin: Created by wind blowing across the water’s surface.
   • Characteristics:
     • Breeze Waves: Small and irregular, formed by light winds.
     • Stationary Waves: Waves that remain almost still and don’t propagate much, typical of weak winds or enclosed areas.
     • Storm Waves: Large and powerful, generated by strong and persistent winds.
   • What They Indicate: The strength and direction of the wind in the area, as well as how long and how much space the wind has acted on the surface of the sea (fetch).
2. Swell
   • Origin: Waves formed by distant storms, propagating for hundreds of kilometers.
   • Characteristics:
     • Long wavelength and regularity.
     • Can be large even without local wind.
   • What They Indicate: Atmospheric conditions or storms in distant areas. Swells allow for predicting weather and sea conditions along a route.
3. Tidal Waves
   • Origin: Created by the gravitational forces exerted by the moon and sun.
   • Characteristics:
     • Cyclical and predictable, with highs and lows that vary based on position and lunar phase.
     • Manifest as regular variations in sea level.
   • What They Indicate: Changes in tides (high and low), essential for navigation in coastal zones and ports.
4. Current Waves (or Internal Waves)
   • Origin: Formed at or beneath the surface where two currents with different densities or speeds meet.
   • Characteristics:
     • Can be visible or hidden.
     • Often found in straits or channels.
   • What They Indicate: Interactions between marine or river currents, which can influence the movement of the boat.
5. Tsunami Waves
   • Origin: Generated by underwater earthquakes, volcanic eruptions, or landslides.
   • Characteristics:
     • Long wavelength, high speed in open sea.
     • Become dangerous near the coast, growing in height.
   • What They Indicate: Underlying geological events. Although rare, they require monitoring in high-risk areas.
6. Backwash Waves (or Refracted Waves)
   • Origin: When waves hit an obstacle (cliffs, shores) and return.
   • Characteristics:
     • Turbulent and often dangerous for those near the coast.
     • Can cause rip currents.
   • What They Indicate: Interactions between waves and the coast, which can create challenging conditions for anchoring or swimming.