A battleship was built to fight with the main fleet, while a battlecruiser needed the speed, range, and engine capacity required for commerce warfare. The Royal Navy was not trying to build another battlecruiser after the Second World War, but the King George V class could not fully cover that older global role. Vanguard therefore combined battleship fighting power with the speed and reach expected of a fast capital ship. Her classification remained unambiguously battleship even as her proportions and intended employment borrowed from cruiser practice.
Chapter · 21:43-24:21
Why Vanguard was a fast battleship, not a battlecruiser
Vanguard remained a battleship even though her speed and range let her cover missions once associated with battlecruisers.