It is a good question Philip.
In my limited experience of trying to sail in the 40 kt + gusts I`ve found it is possible to sheet out (partially) yet still keep fin and mast foot loaded;infact I reckon if you cant do that you simply cant sail in s gusts over 35 k .(roughly). Dont think its possible with all sailsbut certainly with NP combats and to a lesser degree searches...
I`ve also found real problems lie after doing this in trying to gybe;if you are sailing fast in normal conditions as you enter gybe apparent wind can be zero;in insane winds;when you are sailing relatively slower keping rig depowered is a whole new problem. (Shooting off downwind in a 40 knot gust feels suicidal)
Its easy to say keeping speed up is the answer;having bottle to do it is another ;especially as at some stage you wll be bouncing over chop at some stage.
Putting it in perspective with boardspeed/windspeed. I wore GPS last week on 3 sailing sessions.On 7 metre day windspeed max gust was 25 knots. (Generally around 22) V max 29 knots.
On 5 metre day; max wind gust 35 knots (generally 30 knots) Vmax 28 knots
)n 4.5 metre day max gust 42 knots. V max 26 knots !!! Hence problem gybing ???