There are individual kits for the hull, portals, centerboard and rudder, masts, sails, rigging and lines, epoxy and fiberglass.

[1][2] The Core Sound 20 Mark 3 is a recreational keelboat, built predominantly of stitch and glue 6 mm (0.24 in) okume wood, with two unstayed aluminum masts.

It has a loose-footed cat ketch rig with wishbone booms, a slightly raked stem, a plumb transom, a transom-hung rudder controlled by a tiller, a self-draining cockpit and a retractable centerboard keel.

[1] In 2018, the original design was modified to add a mizzen mast tabernacle to allow easier rigging, as well as greater cabin headroom and simplified construction.

Later kits, starting with serial number 20, have a longer centerboard, giving a draft of 3.93 ft (1.20 m).