The OK is a 4 metre (13'3") single handed dinghy. The single sail is carried on an unstayed flexible rotating mast. OKs sail well in winds from imperceptible to way-to-much and on any venue from pond to open sea. They are raced in 16 countries and 4 continents: OK sailors enjoy great racing at every level from club novice to international. Boats are strong and have long competitive lifetimes, so entry costs are low.
Active national class associations and an international association promote racing across the world: the OK is an ISAF international class.