There was an article in (I think Sail) a few months ago about a boat that lost its rudder in a race. They had a large diameter rope anchor rode that they double and then daisy chained. They then attached a small anchor and drug the whole thing behind the boat with the ends coming forward to the genoa lead cars and back to the primary winchs. (I think I got most of the details correct) The rode created enough drag to steer the boat, the anchor kept it submerged, and they winched it to one side or the other like a rudder to steer.
I don't know that I would call that set-up ideal, but good to know about.