The International Yacht Racing Union formulated rules for the International Catamaran Divisions in 1962 with approved amendments in 1963 and 1964. The purpose of these rules was to encourage racing and development within four divisions. It was hoped that International status would be granted to one or more classes within each division.


The first A division catamaran registered in Australia was designed and built by John Smallman of Victoria in 1966.

The first A cats built in Sydney were Graham Johnston’s A-Cat 1 and Harold Stevenson’s Camira. Johnston’s A-Cat went on to become the Australis, winning every race in a selection trial at Blairgowrie in March 1967. This selection trial was for an Australian representative to the I.Y.R.U. trials in England in July 1967 to select catamarans to International status within the 4 divisions. Graham Johnston then took his boat to England and won International status. The Australis Association was formed shortly afterwards.

From there the Australis progressed slowly, was altered slightly and due to decreasing numbers lost it’s International status at the I.Y.R.U. meeting, 5th Nov. 1973. In the meantime the open A class division continued beside the Australis with many different designs being sailed in Australia. Some of these included the Unicorn, Quest A, Buccaneer, Harmony and Rhapsody designs. Of these the most popular was the Unicorn design. In the next few years the Stevenson designed Rhapsody gained greater popularity. Since then we have seen the development of the Hooper designed Colonial designs and the modified Rhapsody designs from Greg Goodall.

All modern designs have been improvements on earlier models.

The greatest breakthrough in design has certainly been in rig development. In the early days rigs were supported by very bendy pear section masts of 27 to 28 foot in length. Since the 1981 Botany Bay World’s where the Australian designed and manufactured Wing Mast came to the fore, sail development has centred on a rig size of 30 to 32 feet. Whilst the Austwing remained popular in the early 1980’s, the Italian Sori mast, and more recently the Goodall copy, with more stiffness has dominated the higher placings in recent championships. The Sydney built Spunspar mast of similar dimensions but not as stiff has also proved popular with the lighter weight sailors in recent years.

In 1987/88 Barry marmion introduced the flat top rig on an untapered Goodall mast. This sail had a cut away leech for greater heavy weather performance and also swept the deck to create an end plate effect. Whilst the flat head has remained popular, the deck sweeper was abandoned shortly afterwards. Various sailmakers have developed these sails further with larger head boards. Some have continued the cut away leech concept, but recently this seems to have lost favour.

No one single design of A cat has proved dominant, thus supporting the principle of open design and development within a class. In Australia today half a dozen different designs are actively campaigned in all Eastern States. Although the trend now-a-days is to Carbon and Kevlar/Glass foam sandwich construction, plywood boats are still to be found actively campaigned.

Following on the trends of Europe, Carbon masts started to enter the Australian market in the 93/94 season, with construction by Jim Boyer. After several teething problems this production was stopped in favour of importing European masts. At the 1996/97 Nationals half the fleet used carbon masts, with several being of home made construction. Carbon masts are being now being produced in commercial quantities in Europe, America and Australia.

Australian sailmakers are equal to the best in the World having the largest number of World champions and used by half the fleet at the 1998 European Championships.

Since 1980 the A class’s performance has improved to the point of dropping 6.5 points on the VYC yardstick ratings.


The International A-Division Catamaran Association (IACA) was founded on 8th May, 1975 with the prime intention to co-ordinate and supervise the activities of the National Associations of A-Division Catamarans. Interest in A cats was then very high in several European countries, North America, Great Britain and Australia. European championships were held from 1975 until 1980 with Kerry Holmes (Qld) the European champion in 1979.

World championships have been held since 1981 with Australians continuing to dominate by winning 11 of these 15 championships.

To date A Cats are sailed in 15 countries throughout the World, covering Great Britain, France, Netherlands,Denmark, Austria, Sweden, Switzerland, Belgium, Germany, Italy, Spain, USA, Canada,New Zealand, Australia.