The International Rule
By the end of the 19th and beginning of the 20th Century, yacht racing had become popular and had spread across Europe. In order for different types of yachts to be able to race together various rating rules and classifications were established, but each country had their own set of different rules, although they were all based on similar principles (the factors that affect the speed of a yacht are governed by the laws of physics - which are the same all around the world!).
These rules were constantly being exploited by designers and the fastest boats were often unseaworthy designs that were very lightly built. It was also the case that yachts were becoming obsolete very soon after being launched, as designers would find new 'loopholes' that allowed faster yachts to be built. This was not a healthy state of affairs and whilst it was perhaps good for designers, it did not encourage yacht owners to take part in racing.
Due to the different rules and classifications that existed in different countries, international yacht racing was always subject to various forms of handicapping, which tended to be quite subjective and open to protest. What was required was a common rating or set of rules that allowed yachts from different countries to race together on equal terms.
In order to try and solve these problems, in 1906 leading yacht racing representatives from various countries in Europe came together to lay down a system for rating yachts, together with measurment rules, construction regulations (to ensure that they were not built too lightly) and racing rules. The International Rule was subsequently ratified in 1907 and adopted by various countries in Europe (the USA attended as observers, but did not adopt the rule until much later as they already had their own version in Herreshoff's Universal Rule).
The rule allowed yachts from different countries to be able to compete on equal terms - a level playing field in each class. There are several classes that come under the International Rule, including 6, 8, 10, 12, 15 and 23 Metres. They are sometimes referred to as 'metre boats'.
Under the rule designers have a certain amount of freedom to design the boat as they see fit (within clearly defined limits as described by the rule and the formula). As such, each yacht built under the rule is unique, although they do tend to have a remarkable 'family resemblance', which is testament to the robust nature of the rule. It is perhaps akin to Formula One car racing, where each car is different, but they compete on level terms without a handicap system.
As a development class, metre boats (and particularly 6 Metres) were at the forefront of many innovations in yacht design and development during the 20th Century, which modern production yachts have benefitted a great deal from (again there are many parallels with Formula One racing here where many innovations have eventually filtered down to production cars on the road).
More to follow soon...