Out at Flinders, taking off on approx head-high waves, getting up to 25 km/hr or more (according to Search GPS watch), I often have trouble pulling off a fast bottom turn. It feels really stiff. I try to lean in but it doesn't always feel like the board wants to turn and sometimes I recover by using the paddle as an outrigger. At lower speed, no worries. So, is it:

1. Me - being a pussy and not committing (digging the rail) hard enough?
2. Me - not having my back foot back far enough (although I do try to get it back)?
3. Me - not having my back foot close enough to the rail?
4. The fins. I am using C-drives now, but I feel like I had the same challenge with the standard fins
5. The board - I am riding an Acid 8'10 116 L and I am 93 kegs.
6. Something else?