Thames Tonnage

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:



where:

• length is the length, in feet, from the stempost to sternpost;
• beam is the maximum beam
  Beam (nautical)
  The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
  
  , in feet.

Godinet rule

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.



where:

• L = LWL
• P = girth of the hull
• S = Sail area
• T = Rule in tons

The Société Nautique de Genève

Société Nautique de Genève

The Société Nautique de Genève is a yacht club based in Geneva . It was founded in 1872 with the goal of developing nautical sports and high level sailors...

, which was an early adopter of the rule, amended it in 1901 to include the skin girth instead of the chain girth.

This new French rule was adopted in December 1892 by Switzerland followed by Germany, Denmark, Finland and Sweden in March 1893. Belgium and Spain completed the list. In March 1894 the Godinet rule is first noted in the United States, at the construction of the Vendenesse, the world's first aluminium yacht.

Some yacht in existence that were designed to the Godinet rule:

• Bona Fide: designed by Charles Sibbick in 1898 to rate as a 5-tonner. It was built at the Albert Yard, Cowes, for J.Howard Taylor, who laterwon the Gold medal in the category 3 to 10 tons at the 1900 Olympics
  Sailing at the 1900 Summer Olympics - 3 to 10 ton
  The 3 – 10 ton was a sailing event on the Sailing at the 1900 Summer Olympics program in Meulan. It was the second-heaviest weight class. The race was held on 25 May 1900. At least 27 sailors, on 11 boats, from 4 nations competed.-Results :...
  
  . This yacht was authentically restored between 1999 and 2003 by the Cantiere Navale dell'Argentario, in Tuscany and is the last 19th century Godinet rater.
• Calypso: designed and built in 1911 to rate as a 3-tonner

Olympic Games

The Ton classes where Olympic classes 1900 and probably also on that of 1896. Unfortunately due to weather conditions the yacht races in 1896 where cancelled and much information of that event is not longer available. For the 1900 events, sailing categories are established based on the Godinet rule:

• 0.5 Ton
• 0.5 – 1 Ton
• 1 - 2 Ton
• 2 - 3 Ton
• 3 - 10 Ton
• 10 – 20 Ton
• Open Class

Olympic results

Ton Class	Rank	Country	Helmsman	Crew	Yacht
0.5			GERVAIS, Pierre		Quand-Même
			TEXIER I	CHARCOT, Jean LINZELER, Robert TEXIER II	Baby
			MONNOT, Henri	TELLIER, Léon CAILLEUX, Gaston	Sarcelle
	4		SACRE, Emile		Fantlet
0.5 – 1			LORD CURRIE, Lorne Campbell	GRETTON, John H. HOPE, Linton MAUDSLAY, Algernon	Scotia
			BAUDRIER, Jacques	MARCOTTE, F MARTIN, William VALTON Jules LE BRET, Jean	Crabe II
			MICHELET, E.	MICHELET, F. MERAN Marcel	Scamasaxe
	4		DE CHABANNE LA PALICE, Jean
1 - 2			COMTE DE POURTALES, Hermann Alexandre	DE POURTALES Hélène DE POURTALES, Bernard	Lérina
			VILAMITJANA, F.	ALBERT, Auguste DUVAL HUGO, Charles	Marthe
			BAUDRIER, Jacques	BAUDRIER, Lucien DUSBOSQ MANTOIS, Edouard	Nina-Claire
2 - 3			EXSHAW, William	BLANCHY Frédéric LE LAVASSEUR Jacques	Ollé
			SUSSE	DOUCET GODINET MIALARET	Favorite
			DONNY, Auguste		Mignon
	4		SCHLATTER, Ferdinand	DE COTTIGNON JEAN-FONTAINE Emile
3 - 10			TAYLOR, Howard	HORE, Edward JEFFERSON, H. N.	Bona Fide
			GUFFLET, Maurice	DUBOS, A. DUBOS, J. GUFFLET, Robert GUIRAIST, Charly	Gitana
			MACHENRY, M.		Frimousse
	4		GILARDONI
	5		SMULDERS, Henricus Petrus	HOOYKAAS, Christoffel VAN DER VELDEN, Arie	Mascotte
10 – 20			BILLARD, Emile	PERQUER, P.	Estérel
			LE DUC DECAZES, Jean		Quand-Même
			HORE, Edward		Laurea
	4		CRONIER
OPEN			LORD CURRIE, Lorne Campbell	GRETTON, John H. HOPE, Linton MAUDSLAY, Algernon	Scotia
			WIESNER, Martin	PETERS, Heinrich WEISE, Ottokar NAUE, Georg	Aschenbrödel
			MICHELET, E.	MICHELET, F.	Turquoise