I see and understand..
in reality, when the wings are added to the mix, the rollup of the vorticies acts much differently in the composite structure...
I would also note the pure laminar flow of the modelling, which in surface vessel, between the attack angle, currents, and the flow from the wings, isnt very realistic, just as in aircraft modelling software, laminar flow from the wings is simplistic and incorrect.
As soon as the vessel is sideslipping or crabbing, in regards to the current, the upstream surface of the keel will create one vortex, while the shielded side will create a different vortex. Modelling software typically deals with the effect of the current on the vortex, rather that the vortex effect from the current...same for aircraft...