Saw a picture once of a boat using a "riding sail" to keep its bow into the wind while at anchor. Perhaps a small triangular sail big enough to keep the aft end away from the wind "weathervane style" would work. It could be fairly small, maybe two feet on the luff with its clue cringle attached to the outhaul fitting at the end of the boom, its head attached to the main halyard, or the line that holds up the boom when the main is douced, and its tack tied to the boom with a small looped line. The boom in turn held amid ships by the main sheet cleated off properly.