What is a J Class

The terminology “J” Class refers to a class of racing yacht, the rules for which were established in 1929 and which resulted in the “J” Class rating for large sailing yachts built between 1929 and 1937 and used to compete in the Americas Cup racing series.

The formula which determines a “J” Class is complicated and relates to the relationship between the sail area and the waterline length but the general design stems from a time when art and design fought for the same space and combined to produce a design which pushed the technology of the time to win races whilst also being a visual spectacle of grace and elegance. These yachts were limited in number, hugely expensive to build and remained the playthings of the very rich. Most were scrapped for the Second World War but more recently there has been a resurgence of interest in the full sized yachts with regular racing of original, rebuilt and replica yachts around the world.

The pictures above are of “Lionheart”, a modern J Class yacht from Hoek Design in the Netherlands. Construction of the 44 metre hull commenced in 2007 and she was launched in 2010. If some modern designs of racing craft epitomise the search for speed over the water, Lionheart epitomises the search for both speed, and grace and elegance.

Lionheart is the inspiration for my one of my own Bermuda rigged Nottingham 48's.

Model makers attribute the title “J” Class to a certain configuration of hull and keel which I refer to as a "full keel" (see Lionheart above) to distinguish it from the more modern 1 Metre or Marblehead model designs where the keel is a fin that drops vertically from the bottom of the hull and carries a torpedo shaped weight at its end. In reality it proves impossible to make a true working replica of a “J” Class as we can’t scale the physics of wind and water so some compromise is necessary! It nevertheless suits our purpose to refer to the smoother shape of the hull as a “J” Class and it is possible to remain faithful to the spirit of the design and also produce a practical working model which is aesthetically pleasing on the eye and which also sails well in a range of wind conditions.

More information on the J Class can be found here: