I sail F18s on the northsea all the time and never have any problem with the surf.
The only time it becomes a problem is with light straight onshore winds and relatively big surf (0.5m), but that is not something that design can solve (unless you fit a motor!).
When its windy the cats with a lot of volume up front can be pushed harder but that isn't specific to the northsea.

I agree that it is a question of technique, but timing is also important.