Paul,
An old saltydog buddy of mine once explained that a bucket on a boat has more uses than any other iten on the boat. Bait well, anchor bin, baling, peeing, barfing, and steering.
Simply tie the bucket to a rope and drag it behind midships whilst slowly making headway. Adjust to starboard or port to steer. Not for use with fine manouvers but might get you to safety. Actually anything with drag will do and probably a bunch of rags or a securely tied coil of rope would work.
Wedge