# Mystere 4.3

1999 — 2004
Designer
Alain Cumming
Builder
Mystere Composites
Associations
?
# Built
?
Hull
Catamaran
Keel
None
Rudder
?
Construction
FG

Length Overall
14 1 / 4.3 m
Waterline Length
?
Beam
4 11 / 1.5 m
Draft
?
Displacement
220 lb / 100 kg
Ballast
?

### Rig and Sails

Type
Sloop
Reported Sail Area
269′² / 25 m²
Total Sail Area
?
Sail Area
?
P
?
E
?
Air Draft
?
Sail Area
?
I
?
J
?
Forestay Length
?

Make
?
Model
?
HP
?
Fuel Type
?
Fuel Capacity
?

### Accomodations

Water Capacity
?
Holding Tank Capacity
?
?
Cabins
?

Hull Speed
?

### Hull Speed

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.

Formula

Classic hull speed formula:

Hull Speed = 1.34 x √LWL

A 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

?
Classic formula: ?
Sail Area/Displacement
117.9
>20: high performance

### Sail Area / Displacement Ratio

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.

Formula

SA/D = SA ÷ (D ÷ 64)2/3

• SA: Sail area in square feet, derived by adding the mainsail area to 100% of the foretriangle area (the lateral area above the deck between the mast and the forestay).
• D: Displacement in pounds.
117.94
<16: under powered
16-20: good performance
>20: high performance
Ballast/Displacement
?

### Ballast / Displacement Ratio

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.

Formula

Ballast / Displacement * 100

?
<40: less stiff, less powerful
>40: stiffer, more powerful
Displacement/Length
?

### Displacement / Length Ratio

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.

Formula

D/L = (D ÷ 2240) ÷ (0.01 x LWL)³

• D: Displacement of the boat in pounds.
• LWL: Waterline length in feet
?
<100: ultralight
100-200: light
200-300: moderate
300-400: heavy
>400: very heavy
Comfort Ratio
?

### Comfort Ratio

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.

Formula

Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam1.33)

• D: Displacement of the boat in pounds
• LWL: Waterline length in feet
• LOA: Length overall in feet
• Beam: Width of boat at the widest point in feet
?
<20: lightweight racing boat
20-30: coastal cruiser
30-40: moderate bluewater cruising boat
40-50: heavy bluewater boat
>50: extremely heavy bluewater boat
Capsize Screening
3.3
>2.0: better suited for coastal cruising

### Capsize Screening Formula

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.

Formula

CSV = Beam ÷ ³√(D / 64)

• Beam: Width of boat at the widest point in feet
• D: Displacement of the boat in pounds
3.3
<2: better suited for ocean passages
>2: better suited for coastal cruising

### Notes

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.”

### For Sale

Have a sailboat to sell?