What is the theme in Sailing Alone Around the World by Joshua Slocum?

Weather conditions are a central theme in this book. Even though Slocum was a seasoned sailor, there were many things to consider along the way, such as unpredictable weather. Slocum details many instances in which the Spray had to weather through violent gales and turbulent waters. The weather often predicated a change of course although Slocum was able to maintain the majority of his route.