Notes: The CAL 21 was equipped with a swing keel that could be completely raised inside a slot/cavity below the cockpit sole. When the keel was down, a plug was dropped into place to cover the opening and make a flush surface around the keel 'root'. A cable had to be attached or re-attached, to raise or lower the keel.\nBesides reducing drag while sailing, the system allowed the hull to sit lower on a trailer.