The design brief for MOONSHINE was to produce a very fast, low cost, easily handled cruising sloop that could be home-built. This design was the starting point of the Farr concept of light displacement, super-efficient cruising yachts. The displacement length ratio chosen for this design was one that Farr felt would be low enough to allow early surfing downwind in seas, and planing in strong winds in flat water, but not so low as to mean insufficient displacement, and therefore ballast, to provide enough stability to be a fast boat to windward.

This displacement length ratio would provide extremely good windward performance hitherto not seen in light displacement boats, plus the downwind characteristics of proven light displacement designs already in existence. Beam was kept quite moderate to produce a fast reaching full form and the bow was significantly finer than had been seen on most light displacement boats, which allowed the boat to handle short steep seas with surprising ease. Once again, as in TITUS CANBY, an efficient keel form was chosen with ballast concentrated low down in the keel to provide good stability to windward. The moderate beam and "U" shaped bow sections meant quite low wetter surface area for a boat of these dimensions. This allowed good performance out of a relatively small sail area even in light conditions. A masthead rig was chosen for its absolute simplicity, though the choice was colored to some degree by conservatism in a design of this size, which was the larges keel boat Farr had designed at that time.