By Yoonjung Seo, Gawon Bae, Brad Lendon, CNN Seoul, South Korea (CNN) — South Korea wants to join the undersea naval elite – and has received the blessing of US President Donald Trump to do just that.

There’s something about the guttural gulp of a pair of Weber carburettors gasping for air that can give even the most prosaic of engines a sense of purpose. Take the Vanguard four-cylinder, cast-iron ...