Dictionary

know the ropes en · VERB

To have experience of the appropriate procedures; know how a particular task or job should be done (with reference to ropes used in sailing).
- A traveller from Pontypridd to Llantrisant, not knowing the ropes, would naturally travel to the station of that name, only to find himself at Pont-y-Clun, two miles distant, and probably would not be at all soothed to discover that, had he alighted at the previous station (known as Cross Inn), he would have been within half a mile of his objective. [the station at Pontyclun was named Llantrisant before it closed, it later reopened as Pontyclun] 1951 March, M. D. Greville, “The Nomenclature of Railway Stations”, in Railway Magazine, page 194:

Spelling	Features	Source
known the ropes	Tense=Past, VerbForm=Part	lexicographic
knew the ropes	Tense=Past	lexicographic
knowing the ropes	Tense=Pres, VerbForm=Part	lexicographic
knows the ropes	Number=Sing, Person=3, Tense=Pres	lexicographic