5.5 Metre

The International 5.5 Metre class was created to yield a racing keel boat that would give a sailing experience similar to that of the International 6 Metre Class but at a lower cost.

The main class regulation restricts a single quantity output from a formula involving the boat's rating length L, weight (expressed as a displacement D) and sail area S; the regulation states that the output of this formula must not exceed 5.500 metres. There is considerable scope for variations in design while still meeting this restriction, and as a result, each 5.5 metre boat is unique.

If the design parameters of a proposed new boat result in a formula output exceeding 5.5 metres, then one or more of the parameters must be suitably adjusted. Performance data gained from testing models towed in a long water tank (referred to in yacht design as a Ship model basin) can suggest optimal combinations of parameters. The 5.5. metre rule is a variant of the International Rule (sailing) established in 1907. The 5.5. is therefore closely related to larger metre boats such as the 6mR, 8mR and the 12mR.

Since 2010, the 5.5 Metre is one of the Vintage Yachting Classes at the Vintage Yachting Games.

History

The 5.5-metre class was a redesign of the 6-metre class by Charles E. Nicholson in 1937. The first boats conforming to the 5.5-metre rule were built in 1949. There had been an earlier attempt to build a cheaper alternative to the Sixes. In 1929, the 5-metre class was established by the French "Union de Societes Nautique Francaise" and was accepted in London. It achieved a position as the smallest new international metre class, and some hundred boats were built. Nevertheless, the 5 metre never managed to achieve an Olympic status. The 5.5-metre class replaced it quickly and was raced in the 1952 Summer Olympics in Helsinki for the first time. The Scandinavian Gold Cup has competed with 5.5m boats since 1953. 5.5 metre boats replaced the International 6-metre at the 1956 Olympic Games in Melbourne, Australia. The 5.5 metre participation in the Olympic sailing events continued at the 1960 and the 1964 Olympic Games. During the 1960s; however, it began to draw similar criticism as the preceding six-metre class - namely, increasing costs - and the boat lost Olympic status after the 1968 Olympic Games, due to excessive design and building costs of one-off boats, marking the end of development class keel boats in Olympic regattas. However, the class remained active thereafter, and 5.5-metre boats are still very actively raced.

The formula

The measurement formula is given in the :

5.500 metres ≥ 0.9 ⋅ ( L ⋅ S 2 12 ⋅ D 3 + L + S 2 4 ) {\displaystyle 5.500{\mbox{ metres}}\geq 0.9\cdot \left({\frac {L\cdot {\sqrt[{2}]{S}}}{12\cdot {\sqrt[{3}]{D}}}}+{\frac {L+{\sqrt[{2}]{S}}}{4}}\right)}

where

• L {\displaystyle L} = length for rating
• S {\displaystyle S} = measured sail area
• D {\displaystyle D} = displacement in cubic metres

Events

Olympic Games

World Championship

Vintage Yachting Games

Pan American Games

European Championships

Scandinavian Gold Cup

Class association

The object of the International 5.5 Metre Class Association is to promote and develop 5.5 Metre racing throughout the World. The first President of the association was Mr. Owen Aisher.

Since the development of the class spanned more than half a century, the early boats are not competitive in racing against the modern designs. Therefore, the association made, in 2007, divisions in the class based upon the age of the boat:

• Classic Fleet (Designs before 1970)
• Evolution Fleet
• Modern Fleet (Designs from 1994)

During major races, there are separate trophies per fleet; however, if a classic fleet boat beats the modern fleet, the classic fleet boat wins the modern fleet trophy.

External links