The International 505 is a one-design high-performance two-person monohull planing centreboard dinghy, with spinnaker, using a trapeze for the crew. While it is a high-performance boat and demanding in a blow, the 505 is an extraordinarily well-handling craft and is easier to control than many smaller trapeze boats.
The genesis of the class was in 1953 with the creation of the 18-foot 'Coronet' dinghy designed by John Westell. This sailboat competed in the International Yacht Racing Union (IYRU) selection trials at La Baule, France, in 1953 for a new two-person performance dinghy for the Olympics. Although the Coronet lost Olympic selection to the Flying Dutchman (even though its performance was notably superior), in 1954 the Caneton Association of France asked Westell to modify his Coronet design to create for them a 5-meter performance dinghy that would be suitable to their needs. Westell settled on a measured length 5.05 m to allow for boat-building tolerances of the day, and the resulting craft become known as the 505. The class achieved international status with the IYRU in 1955.
The 505 is a very popular international class and is raced actively in 18 countries around the world, with the largest numbers in Germany, the US, UK and Australia. World championships are held every year at locations around the world, alternating between Europe, North America and Southern Hemisphere countries, and consistently attract over 100 boats to the start line. At the 2005 World Championships held in Warnemünde, Germany there were 171 boats. The 505 may also be sailed in a mixed fleet using the Portsmouth Yardstick handicap scheme. Its Portsmouth number (administered in the UK) is 902 and its D-PN (administered in the USA) is 79.8 .
There are not many fleets in the conventional sense of boats parked side-by-side at a club and regular attendance at series-type 'club racing' is not typical for this class. The ease of trailering and storage of the boat coupled with its complexity, which makes it both engaging to tinker with and somewhat risky to leave untended in a parking lot, has led to many owners keeping their boats at home. Fleets are essentially collectives of sailors that keep in touch and train together at a convenient facility for the regional 505 event calendar, which may include perennial fixtures as well as regional, national or world championship regattas. Europe in particular has a well-attended calendar of events that attracts sailors from all over the continent because of the ease of travel and excellent venues (Hyeres, Lake Garda, Kiel, etc.).
Locales that have established core groups of 505 sailors are as follows:
The hulls of early 505s were built in cold-molded marine plywood. Many of these are still actively raced. New hulls are now built using composite molding: glass fibre and/or carbon fibre mats and vinylester or epoxy resin using either a wet layup technique or using heat-cured prepreg sheets. Hulls are usually cored with foam, balsa or Nomex to increase stiffness and durability: new hulls will remain competitive for well over ten years, and boats several times that age have won races in major championships. Spars traditionally were aluminum alloy, but recent rule changes have permitted the use of carbon fibre for booms and spinnaker poles (though not for masts.) The hull shape and sail plan are tightly controlled, while the spars, foils and rigging are more open. This allows the boat's rig and controls to be set up to the preferences of the sailor, rather than dictated by the class rules (as they are for the Laser class, for example.) The rig itself is highly adjustable for wind and sea conditions, with the result that the boat can be sailed in a relatively wide range of wind speeds and by crews of varying sizes. Successful teams come in many combinations, including all-female, all-male, mixed, and child/adult or child/teen. As of 2009, over 9000 505s had been built.
There have been many builders over the 60-year history of the class. At present Rondar Raceboats is the most prolific builder, producing wet-layup hulls on a semi-production basis. Ovington Boats, which at one time built hulls for Rondar under contract, now build their own.
List of current 505 hull builders:
It is typical for sailors to purchase bare hulls, spars and foils, and then rig the boats themselves. The result is that there is a wide variety of setups, with some notable regional preferences. For example, US boats traditionally have end-boom sheeting while German boats have mid-boom. This has led to the establishment of several rigging businesses, led by successful 505 sailors, that have developed standard rigging setups and sell complete boats based on bare hulls sourced from builders. These include Holger Jess with SegelsportJESS in Kiel, GER and Ian Pinnell of Pinnell & Bax in Northampton, GBR. Having standard setups with published tuning settings helps non-professional sailors become competitive more quickly. Similarly with sails. There are a handful of sailmakers that dominate the 505 class: Pinnell & Bax in the UK, Bojsen-Møller in Europe, and Glaser and North in the US.
The 505 is a big boat by dinghy standards, with a powerful sailplan, especially with the adoption in 2002(?) of a much larger spinnaker. It is generally considered a class for adults, with world class crews usually having a combined weight in the range of 150 to 185 kg. It is remarkably well-balanced under main and jib, even in big breeze: many boats use a fixed tiller/rudder requiring beach launched boats to be sailed without a rudder into deeper water. The 505 will plane upwind in windspeeds of around 10 knots or more. Offwind, the 505 is very exciting, but still well-behaved. In winds above 12 knots it is usually advantageous to "tack downwind", utilizing the apparent wind advantages of broad-reaching, rather sailing downwind. With a big spinnaker and conventional pole, gybing in a breeze is a particularly challenging manoeuver and pulling it off consistently is the defining "rite of passage" between novice and skilled crews.
Even after 60 years, the 505 remains one of the most sophisticated and rewarding sailboats to sail. The list of 505 "alumnae" includes many of the world's top professional sailors, many of whom attend major 505 events to keep their sailing skills sharp.
The 505 has a track record for adopting technological advances in the sport, keeping the class current and relevant but without rendering existing boats obsolete. Experimental modifications to the accepted design, i.e. outside of the class rules, have been conducted at different points in history. Such modifications have included setting up a double-trapeze system, installation of a bowsprit, and inclusion of an asymmetric spinnaker. To date these have not been adopted by the 505 Class Association.