Rudders can stall and when they do they cause huge drag while becoming ineffective at turning a boat.
In general flat, narrow rudders are most prone to stalling. The elliptical rudder on the Epic V10 is one of the most effective rudders - look at the profile and you'll see a proper airfoil cross section. Of course if you're going too slowly or the rudder's not in the water, the airfoil section won't matter a damn!
If you're in a situation where the rudder is stalling - hard over but not turning the ski - you can try straightening the rudder momentarily to get the water flowing over it again.
But as Nell said, the key is speed; you have to be going faster than the wave. If the crests of the waves are close together, you may have to go down them diagonally to stop ramming the next wave in front, but then... you need to be going at speed or you will broach!
Rob
Currently Epic V10 Elite, Epic V10 Double.
Previously: Swordfish S, Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...