David...our RAN vessels use US compatible RAS ship receival connections for obvious reasons....[like a US refueler embarked with a US/RAN Naval exercise]
You may find all Countries aligned with NATO have their Naval vessels similarily equipped?...or taking it further, any Countries [vessels] currently aligned with the US Government Policy........Japan, The Phillipines, Vietnam?.....the list is mindless
The RAS hosed themselves are 4" bore, so the connection mouthpiece [lighweight non-corrosive stainless alloy] would be a nominal say ~~ 5" convoluted OD max
Derek