Thanks Windxtasy.
I followed that thread and for me it's the opposite.
The Venom goes really well up-wind for me. It works well everywhere until the board leaves the water and lands back in, when it loses traction and I end up going sideways.
I accept that the poor technique has a lot to do with it.
Goldwing works better at Pinnaroo Point for me, but then again, I use Goldwing with a FSW board and Vendom with Futura. And I use Futura on the river, where it hits the chop faster.
Either way, you answered the question I had about the curved fin shape.
It won't produce more traction and will produce less lift