# 10 Metre (keelboat)

Current Specifications
Class Symbol
Crew 8
LOA 16.5 m (54 ft)
LWL 11 m (36 ft)
Beam 3 m (9.8 ft)
Draft 2.2 m (7 ft 3 in)
Hull weight 12,000 kg (26,000 lb)
Infobox last updated: 14-APR-2010
Former Olympic Class

The International Ten Metre Class is a construction class, meaning that the boats are not identical but are all designed to meet specific measurement formula, in this case International Rule. At their heyday, Metre Classes were the most important group of international yacht racing classes, and they are still actively raced around the world. "Ten" in class name does not, somewhat confusingly, refer to length of the boat, but product of the formula; 10mR boats are, on average, 16.5 meters long.

## History

The 10mR was used as an Olympic Class during the 1912 and 1920 Olympics. The International Rule was set up in 1907 to replace earlier, simpler handicap system which were often local or at best, national, and often also fairly simple, producing extreme boats which were fast but lightly constructed and impractical. The rule changes several times in history. About 20 boats were ever build.

## Rule development

### 1907 Rule

Used from 1907–1920

$10.000 \mbox{ metres} = \frac{L + B + 1/3G +3d + 1/3\sqrt{S} - F}{2}$

where

• $L$ = waterline length (LWL)
• $B$ = beam
• $G$ = chain girth
• $d$ = difference between girth and chain
• $S$ = sail area
• $F$ = freeboard

### 1919 Rule

Used from 1920–1933

$10.000 \mbox{ metres} = \frac{L + 0.25G +2d + \sqrt{S} - F}{2.5}$

where

• $L$ = waterline length (LWL)
• $G$ = chain girth
• $d$ = difference between girth and chain
• $S$ = sail area
• $F$ = freeboard

## Olympic results

Event Gold Silver Bronze
1912:
Sweden

details
1920:
Belgium

1907 rule
details

No further competitors

No further competitors

1920:
Belgium

1919 rule
details

No further competitors

No further competitors