15 Metre

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The 15 Metre class (15mR) yachts were built under the First International Rule of 1907. Twenty boats were produced between 1907 and 1917, and four of them have survived and are still raced today.

The IYRU, later known as the International Yacht Racing Union, created the 1907 rule to replace the older YRA system from 1901 and to open international competition. The 15mR boats followed the first 1907 rule, and the boats were built for competition in Spain, France, Britain, and Germany. The rule was updated a few times, but the 15mR boats raced under the original 1907 standard. The 1908 Olympics were proposed for this class, but there were no entries.

The 15mR is a construction class, meaning boats are designed to meet specific measurements in a rating formula rather than being identical. At their peak, Metre classes were the most important international yacht racing groups, and they are still raced worldwide. The term “Metre” refers to the rating, not the boat length; 15mR boats have an overall length of about 30 metres (roughly 98 feet).

The rating formula used in the First International Rule (1907–1920) is:
15 m = (L + B + 1/2 G + 3 d + 1/3 sqrt(S) − F) / 2
where L, B, G, d, S, and F are specific measurements of the hull and rig.