The WS IRSA Ten Rater Class

These boats are not limited in length and have overhangs beyond their waterline endings making them light, sleek, seaworthy and fast. This WS IRSA  international rule is based on the 1887 ‘length and sail area rule’ which allows short waterline length boats to have a big sail area and longer LWL boats have smaller sails.

It is an ‘open’ rule with great freedom to develop design and construction, particularly in rigs and sail plans.Many boats can be measured as a 10 rater and several Marbleheads have been successful in the class by conversion with just one larger rig giving 40% extra sail area..