How does Steinbeck compare staying on course at sea to achieving a goal in life in the book, The Log from the Sea of Cortez?

According to Steinbeck, trying to keep a course at sea requires a lot of skill to overcome factors that are beyond one's control. These factors include waves, currents, winds and the condition of the vessel itself. One's abilities to navigate and sail the seas are put to the test when faced with all these difficulties. Similarly, in life when one is pursuing a goal there are many difficulties that should be hurdled.