Why US and British wartime fleets were not interchangeable

How would the Royal Navy and US Navy have fared if they swapped fleets during the Second World War?

The swap would expose mission mismatches, especially because British ships were shaped by Mediterranean air threats and long-distance operations in the Far East.

Many US Navy ships would work in the Battle of the Atlantic but would be less attractive for the Royal Navy's early Mediterranean campaign. British design and fleet choices were shaped by fighting near hostile land-based air in the Mediterranean and by operating far from industrial support in the Far East. Fleets are products of geography and missions rather than collections of ships that can simply exchange flags.