One-Design

One-Design is a racing method where all vehicles or boats have identical or very similar designs or models. It is also known as Spec series. It is heavily used in sailboat racing. All competitors in a race are then judged based on a single start time. One-Design can be contrasted with the Development class, the classic example being the America's Cup 12-metre class, or to the Box Rule used, for example, in the TP 52 class.

A fourth category, the formula based class setup, is sometimes confused with one-design. The Mini Transat 6.50, the Volvo Open 70 monohull, the large ORMA trimaran, and the Formula 18 racing beach catamaran are the exponents of the formula approach. Class-legal boats race each other without any handicap calculations in both setups. However, under one-design the boats are virtually identical except in details, while the Formula setup allows the boats to differ much more in design while keeping a few important specifications the same. As a result the identifier "One-Design" has been used more and more exclusively to denote a class that races only identical boats.