Francais | English | Espanõl

From Wikipedia, the free encyclopedia

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

The main class regulation is a restriction on 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 'tank testing') can suggest optimal combinations of parameters.

The first boats conforming to the 5.5 metre rule were built in 1949. The 5.5 metre design was very successful and replaced the International 6 Metre as a class sailed in the Olympic Games.

[edit] The Formula

The measurement formula is given in the 2006 International Five Point Five Metre Rating Rules:

<math>

5.500 \mbox{ metres} \ge 0.9 \cdot \left( \frac{L \cdot \sqrt[2]{S}} {12 \cdot \sqrt[3]{D}} + \frac{L \cdot \sqrt[2]{S}} {4} \right) </math>

where

• <math>L</math> = length for rating
• <math>S</math> = measured sail area
• <math>D</math> = displacement in cubic metres

[edit] External links

• Official International 5.5 Metre Class website