I have no first hand knowledge of heaving to in a catboat, but I would try blowing the mainsheet on a close reach, let her stall out, then lash the tiller over so that the rudder is hard to weather.  My thinking is that the windage on the freeboard plus any drag on the sail will cancel out the rudder.

   I have no experience with a Skerry but plenty on a catboat. Raising the center board is important and when the main sheet is let out and all forward speed is lost lashing the tiller loosely down wind will result in a nice steady platform.

Tiller to leeward, sheet slighty started (eased), which I think is another way of saying what Cap'n Skully said above.  Play with those two variables until she lies quietly (drifting slowly across and down wind) with her head maybe 5 points off the wind.  You might need to pull the daggerboard up some, as well.  Every boat is a bit different.  Works to some extent in a catboat (I have one of those, as well as lug-rigged Passagemekar), if the wind ain't too gusty and shifty, but not as well as it does in a sloop with a jib to back.

Probably works better in a heavier boat than a light one.  You'll want to keep a sharp eye on her, so she don't tack herself and then immediately gybe, which could be troublesome if there is much weight to the wind.

The general idea of heaving to in a boat with a single sail is much the same as with a sloop: if the boat falls off enough to fill the mainsail, this will create forward momemtum.  Having the tiller lashed off to leeward, she'll (hopefully) round up before she gets much way on, which'll cause the wind to spill out of the main and she'll fall back off, backing down on her rudder and turning back away from the wind.

In a sloop, we'd have the backed jib, of course, to make sure she don't come through stays.  With a cat rig, there's no jib to back and there's more of a chance she'll tack herself after a gust.  This is ironic, as catboats in general are notorious for failing to come through stays cleanly when you want 'em to tack, and then getting hung up in irons, if you don't tickle 'em just right.  Well, what do you expect?  Cats are independent minded like that; can't get 'em to sit or roll over or fetch the paper or other such tricks....  <;-)

.....Michael