Ton class

Ton classes are categories used to identify classes of yachts.

Early attempts at creating rating rules were based on the British "old tonnage measurement" system to calculate the volume of the hold of large commercial ships. It gave the vessel's carrying capacity in tons (at 35 cubic feet per ton) or, as some believe, in tuns. Sail area was not included, of course, nor were any credits given for less efficient rigs so, naturally, in the yacht-racing field the cutters predominated. Eventually, this rule was modified in 1854 as the Thames Measurement Rule:

${\displaystyle {ThamesTonnage}={\frac {({length}-{beam})\times {beam}^{2}}{188}}}$

where:

The Godinet rule was adopted in 1892 by the "Union des yachts français", and was quickly adopted by other nations from the European continental. It allowed the classifications of yachts by tons, with a formula established by Auguste Godinet which considers displacement, length, and the total sail area.

${\displaystyle T={\frac {(L-0.25P)\cdot P\cdot {\sqrt {S}}}{130}}}$

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