To the Hawaiian, the ocean was the embodiment of the "akua" Kanaloa. Kanaloa was lord over the winds that blew over the ocean, ocean swells generated by those winds  and ocean currents.  The very rising and falling of the tides was caused by the inhaling and exhaling of the the breath (the "Ha") of KanaloaKanaloa was also the akua of navigation.

The portion of the ocean that is visible from land is called Kai.  The ocean that is beyond the horizon and not visible from land is called Moana.

Ale, are ocean swells that travel long distances over the open ocean while waves that break on the shore are called Nalu.

The most common and numerous waves found in the ocean are created by wind blowing across the surface of the ocean. (As compared to waves caused by landslides, earth quakes) The wind, through friction, transfers some of its energy into the water which then takes the form of waves.

 

These waves are not the movement of water but the movement of energy through the water. The height and strength of a wave is determined by three factors; the strength of the wind blowing, the distance the wind blows across the water, and the length of time the wind blows. The stronger the wind; the longer the distance the wind travels along the surface of the water and the longer the time the wind continues to blow, the larger the waves. These “wind waves” tend to be choppy and bumpy and lose power and strength as soon as they leave the area in which the wind is blowing.

 

The winds creating these “wind waves” do not blow at a consistent speed all the time but vary in strength and duration. This gusting behavior of wind, creates waves that travel at different speeds. Where the winds blow over long distances (ie Hundreds of miles) “wind waves”, traveling at similar speeds tend merge creating an ocean swell. This resulting Swell contains enough energy that allows it to travel well beyond the immediate area of the storm. They are no longer dependent on the wind to maintain their energy level. When these swells leave the turmoil of the storm area, they escape the chop and become more uniform and consistent.

 

These swells travel thousands of miles without losing much energy. It is these swells that help non instrument navigators find their way across the sea. Swells, traveling at similar speeds tend to travel together in packs or what are sometimes called Swell sets. In Hawaiian they are called Haʻanopu.