Depends on the boat... a Cal 40 has a short rig and longish keel (ie it resists rapid turns) and with a decent autopilot will go all day and night in 25k with the chute up (and a quartering sea). Being able to sleep in these conditions is the hardest part. Now when it gets much above 25k of wind... yes a shy kite will keep the AP working... at 28k its time to drop the chute (at least with a moderate cost AP setup on a stable boat). Now how those southern ocean racers keep chutes up in the 30K+ range... god only knows. :-)