The Sundance 20 utilizes a swing keel system. This entails a heavy metal keel that is hung on a pivot and can be retracted into the hull to make the boat more easily trailerable. The Keel is raised and lowered by means of a winch system - very similar to the winch used on a boat trailer - with the addition of a clutch system.
The Keel is retracted via a stainless steel cable that is routed through the hull into a hole in the cast keel. this cable should be periodically inspected for fraying, etc… and replaced as necessary.
Per the designer/builder, Len Ferry (Still active on the El Mar Boats FB group), the pivot pin for the Keel is encased in fiberglass during the hull build-up process and is not easily serviceable. If the need arises for it to be replaced, the fiberglass would need to be ground away to give access to the pin.