To be familiar with a task.
Up until the 20th Century sailing ships had vast numbers of ropes and a crewman would not be effective unless he 'knew all the ropes'.
The first known appearance in print is in Richard Henry Dana's Two Years Before The Mast in 1840, in which he wrote 'the captain, who ....knew the ropes, took the steering oar.'
More expressions and their source
Challenge yourself with BookBrowse Wordplays
Your guide toexceptional books
BookBrowse seeks out and recommends the best in contemporary fiction and nonfiction—books that not only engage and entertain but also deepen our understanding of ourselves and the world around us.