anchor v sailing at anchor

Nothing multi-hull specific, but if you're using a second anchor to allievate sailing-at-anchor, you might consider an old sailing ship technique called "Anchor under foot".

Set the first anchor and hook up the bridle as normal. Then, drop the second anchor directly down off the bow. Ease out only about 10' of rode more than the depth of the water.

The idea is that when the boat starts to sail off, the nearly vertical anchor causes enough resistance that the bow slows down and the stern catches up. The boat still sails back and forth a bit, but it really just wags it's tail in the wind - the bow's left/right movement is way less than a boat length.

I've done this a lot with just a 10 pound dinghy anchor dropped off the bow of an 18 ton boat. Works great.