Mahan’s influence is why we have "Blue Water Navies" today. He taught the world that you can’t be a Great Power without a Great Navy. He turned the ocean from a "moat" that protected nations into a "bridge" for their ambition.
Mahan looked at the history of Great Britain and realized something profound: Britain didn't rule the world because they had the best soldiers, but because they owned the The Influence of Sea Power upon History: 1660-1783
translated it and used it as a manual to build the fleet that would eventually shock the world at the Battle of Tsushima. Mahan’s influence is why we have "Blue Water Navies" today