World War 2 Battleships
Naval warfare changed dramatically during the war, with the ascent of the aircraft carrier, and the impact of increasingly capable submarines.
Destroyers saw dramatic improvements, as the Fubuki-class destroyer set a new standard not only for Japanese vessels, but for navies around the world, and are considered to be the world's first modern destroyer.
Submarines were critical in the Pacific and Atlantic theatres.
Advances in submarine technology included the snorkel, though advanced German submarine types came into service too late to impact the war effort.
The German Kriegsmarine also introduced the pocket battleship, to get around constraints imposed by the Treaty of Versailles.
Naval innovations included the use of diesel engines, and welded rather than riveted hulls.
But the most important naval advances were in the field of anti-submarine warfare.
Driven by the desperate necessity of keeping Britain and Japan supplied by sea, technologies for the detection and destruction of submarines were a high priority.
While Japanese efforts proved futile, the Allied use of ASDIC (SONAR) became widespread as did the installation of shipboard and airborne radar.
The construction and launch of new ships during the war was limited due to protracted development and production timelines, but important developments were often retrofitted to older vessels