Dacron (woven polyester)

"Dacron" is a brand name for polyester fibre that long ago became the everyday word for woven polyester sailcloth. It is a genuine weave: yarns running along the roll (warp) and across it (fill), with resin worked in to lock the weave and resist stretch.

Its virtues are the ones cruisers actually need. It is tough, it tolerates being flogged, folded, left on the boom and generally lived with, it takes UV better than most alternatives, and it is repairable anywhere in the world.

Its limit is stretch: under real load a woven cloth gives, and the draft moves aft over the years. That is the trade you accept — and for the large majority of boats it is the right one.