5 Metre
5 Metre is a development sailing class of French origin.

History
The 5 Metre rule was created in France in 1929 and not a according of the International rule in contrast to other Metre yachts.

The formula 
The measurement formula is given in the 2021 International Five Metre Rating Rules:

where
  = length for rating (as defined by rule 3.4)
  = measured sail area
  = freeboard in metres (as defined by rule 3.5)
  = width in metres (as defined by rule 3.6)

See also
5.5 Metre

References

External links
 The Five – sporty open racer for a group of three

Keelboats
Development sailing classes