At the start of the war the three most prominent naval powers were Britain, Japan, and the US. On paper the UK was the most powerful followed by the US, but the reality was much different. Britain had her assets spread throughout her empire while the US navy was split between the Atlantic and the Pacific. Japan not only had the most assets regionally, but was far more developed in modern carrier tactics, night fighting, and ship-borne torpedo warfare. Likewise Germany was the most adept at unrestricted submarine warfare on commercial shipping. Both proved difficult challenges for the allies.

By 1942 the British East Indies was decimated and the American pacific fleet had suffered heavy damage. Luckily for the allies Japan had suffered losses it couldn’t recover from. By 1943 the US war machine was in full swing and new carriers battleships and cruisers were being produced in ever increasing numbers. Early torpedo problems were corrected, new and improved aircraft were made, and developments in anti-aircraft systems were put in place. American submarines were becoming increasingly devastating on Japan’s merchant marine and the navy began winning more decisive fleet battles. I would say by this time the US navy became the predominant naval force with it’s tactics, technology, and sheer numbers eclipsing every nation on earth.