So when a lubber sez to another lubber he sez, “Hey John, the boss told me to show you the ropes,” it means he be teaching John about they job. Stap me vitals, that be a waste of a epic phrase!
Here be how I sees it going down. Say you gots you a swabby with some important poop he not be spilling. You dangles they ropes in front of his mug like so:
When he spots those ropes he be singing his guts out like as if he be in a fancy schmancy opera. Yo ho ho, he be telling you things you not even be asking.