ARTICLE EXCERPT: 
"Stationary or Moving While
 Hove-to?"By Zack Smith October 2000 Latitude 38

.."While testing para-anchors on various vessels off the west coast, I've learned that all sailboats will begin sailing forward while in a hove to station--especially if they have too big a sail plan. If the wind is blowing hard enough, the boat may drift to leeward while still moving forward at about a knot. This is still considered safe as long as the boat doesn't start moving forward so quickly that the slapping action of the waves become a problem.
The best way to prevent this from happening is to use a para-anchor, which slows the
boat's forward progress and effectively keeps her in her own protective slick. I intentionally sail my vessel forward, because the drag from the para-anchor's canopy lets the boat stay in a hove to position without a bridle. As the sea's action increases to storm level or higher, I rig a pendant line to the anchor rode and form a bridle. I've also found that I must always consider the factors of balance--sail plan, rudder position, and length of the anchor rode--because together they dictate how comfortable it is to maintain a hove to position..."