The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.
Classic hull speed formula:
Hull Speed = 1.34 x √LWLA more accurate formula devised by Dave Gerr in The Propeller Handbook replaces the Speed/Length ratio constant of 1.34 with a calculation based on the Displacement/Length ratio.
Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio.311
Hull Speed = Max Speed/Length ratio x √LWL
A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.
SA/D = SA ÷ (D ÷ 64)2/3
A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.
Ballast / Displacement * 100
A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.
D/L = (D ÷ 2240) ÷ (0.01 x LWL)³
This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.
Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam1.33)
This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.
CSV = Beam ÷ ³√(D / 64)
Originally called the MYSTERE TYCA and intended for sailing schools, resorts, and rental facilities.
A number were exported to the US.
This from the class (US) web site.
“In 1980, Yves Sansoucy started manufacturing catamarans as his sailing school had difficulty obtaining parts for their imported boats. He started with larger 6.0 meter boats and moved to smaller boats later. The 4.3 began its life in 1999 as a Mystere Tyca designed by Alain Cumming for French training schools. A sudden dip in the economy in France left Yves with excess stock of 4.3’s. Yves contacted Mike Fahle, a long time Mystere racer, and the wheels went into motion. As a complete volunteer effort, Mike led the Ohio sailors through the delivery of 30 new boats in April 2001. All of these were committed over a few months, sight-unseen, with only a few grainy pictures of European Tycas. The boat filled a void between the simple Hobie Wave and the popular high-tech 20’s that were really too big for small lake sailing. Following quickly from the popularity, Yves agreed to provide the 2002 US Youth Nationals with 20 4.3s. Mike again orchestrated the sale of these boats mostly to Ohio sailors. The result has been a solid, sustained one design class for Ohio and neighboring state sailors. A few boats have strayed as far as Texas and Florida but the majority remain in the Ohio area. With the decline in boat sales and general economic conditions, Mystere is no longer producing boats.”
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