Anchored in 70 knots, you need to reduce windage.  Apart from dropping the booms/mainsails onto the deck and taking in the washing, there is not much else to do on a harry.  If you have time, head for shelter or the open sea and enough sea room to stream a parachute, (much easier on a harryproa than a cat or tri as you are not on the foredeck), lift the rudders, drop the sails, go below with a good book.   Length, beam, low windage, low draft, no cockpit to fill with water and proximity of lines to the crew make this a safe option up to very high winds and big seas.  

If you are caught on a lee shore, you have 4 options.  1) get a second anchor out.  The big tender helps a lot with this. Lowering the second anchor (or any weight) down the anchor line to just above the bottom will also help.  2)   Motor away.  Works as long as you don't pick up any lines or rubbish and the motor is powerful enough to maintain headway, most aren't.  3) Sail away.  This is far easier and safer in a shunting boat with deep (70-80%) reefs on low windage rigs than on a tacking boat where they have to set enough sail to provide enough speed to tack.  4) Drift onto the beach.  If the anchor is dropped just outside the surf line and the boat is allowed to wash ashore, it will end up in shallow water above the wave impact zone pointing into the spent waves.  As the tide comes in, ease the anchor and move up the beach.  When the tide turns, you are safe.  Winch it off at high tide.  

The hassles of conventional boats getting off a lee shore in a gale was one of the reasons harrys were first designed.  I can't think of anything I would add/subtract that would make them better at this than they are.  Suggestions are welcome.