Whose head is covered with fate, Holding the horizon divided, Only the navel is the key to my "Whose head is covered by fate, Holding a wave on the horizon Only the flow my navel is the key to free?

This riddle is referring to a ship. The "head" of the ship is covered by fate (meaning it is guided by destiny), it holds the horizon divided (sailing across the sea), and the navel (center) of the ship is the key to its freedom (allowing it to navigate and move freely).

Coconut