|We dive at five!|
The first British nuclear submarine, HMS Dreadnought [Is it just me, or is that a great name for a warship?] was built using the a US reactor and machinery set, identical to that fitted to the Skipjack class SSN.
For those with longer memories HMS Dreadnought was the first steam turbine-powered battleship in the modern sense and totally revolutionised warship design. It rendered all opposition obsolete overnight and became a byword for a whole generation of warships.
See here: HMS Dreadnought