I started pondering on making a detailed map of oceanic current a while ago (April 2019 to be exact). The goal is to end up with something like this. I haven't dived far into this idea yet but I decided to post it here in the meantime.
I will be using the Guild world project as the base map.

So far, I mapped the main currents in a crude manner. It has no color for the moment as temperatures are not my priority.

Main currents crude.jpg