One of the advantages of the British tendency to use carrier bags for sails is that the material stretcches and its elastic limit is reasonably high. It can therefore be used satisfactoruily in combination with bendy masts.
However, most supermarket carrier bags are quitre heavy material that is not ideal for very light winds. As usual, Roger Stollery is one ahead of the fame and suggests freezer bags and the kind of bag your suit comes back from the dry cleaners in. Anyone have any alternative sources for similar polyethylene sheet - preferably not transparent?