OK. Down wind in heavy+ winds, can you sheet tight and travel in to reduce attack angle?
If it is really heavy plus survival, you may come to a ddw course where you can sheet in, but you will never come out of it. Don't ask why I know...
The survival mode is head in the wind, take boards and rudders up, sit on the bow (hold tight) and sheet in. YOu can any time go back and sail upwind. Works also in surf.
Cheers,
Klaus