Thanks, in the scenario I was thinking about the boat was actively sailing backwards, not simply drifting backwards, but it is good to have clarity on "backing sails", although I would be surprised to know their are no cases listed in a judge book somewhere.

I always assumed in match racing the backing up was precarious for both, since they were both doing it. I think it is a bit naive to define it as using backing of sails to sail backwards, as clearly in many cases it is the rigging / windage that is pushing them back.

Ah well, thems the rules I guess :-)