International Ten Rater (10R)
The International Ten Rater (10R) is one of radio sailing's oldest and most exciting development classes, with a history extending back to the earliest days of competitive model yacht racing. Ten Raters are renowned for being light, narrow, stable, seaworthy and exceptionally fast.
The class is governed by an IRSA International Class Rule based on the historic 1887 Length and Sail Area Rating Rule. Rather than restricting the overall length of the yacht, the rule establishes a relationship between waterline length and sail area. A shorter waterline length allows a greater sail area, while a longer waterline requires a smaller sail area. This creates an interesting design challenge, with designers seeking the optimum balance between hull dimensions, sail area and performance.
Boats in the Ten Rater class are not limited in overall length by the class rules and commonly feature substantial bow and stern overhangs extending beyond the ends of their measured waterline. As the yacht heels and the overhangs become immersed, the effective sailing waterline can increase, contributing to the impressive performance for which the class is known.
The Ten Rater is an open development class, providing considerable freedom to explore different hull forms, foils, construction techniques, rigs and sail plans. This design freedom has resulted in many different hull shapes and design philosophies appearing throughout the class's long history.
Modern Ten Raters typically range from approximately 1.3 to 1.8 metres in overall length, with deep fins and powerful sail plans. Contemporary boats make extensive use of advanced materials and are commonly constructed almost entirely from carbon fibre, including the hull, foils, spars and many fittings.
Fast, powerful and technically challenging, the International Ten Rater continues to provide considerable scope for innovation and development while retaining the distinctive rating principle that has defined the class for more than a century.