Specs
- Designers
- ?
- Builders
- ?
- Association
- C-Class Catamarans Official Web Site
- # Built
- ?
- Hull
- Catamaran
- Keel
- Twin Daggerboard
- Rudder
- ?
- Construction
- ?
Dimensions
- Length Overall
- 25′ 0″ / 7.6 m
- Waterline Length
- 25′ 0″ / 7.6 m
- Beam
- 14′ 0″ / 4.3 m
- Draft
- ?
- Displacement
- ?
- Ballast
- ?
Rig and Sails
- Type
- Cat
- Reported Sail Area
- 300′² / 27.9 m²
- Total Sail Area
- ?
Mainsail
- Sail Area
- ?
- P
- ?
- E
- ?
- Air Draft
- ?
Foresail
- Sail Area
- ?
- I
- ?
- J
- ?
- Forestay Length
- ?
Auxilary Power
- Make
- ?
- Model
- ?
- HP
- ?
- Fuel Type
- ?
- Fuel Capacity
- ?
- Engine Hours
- ?
Accomodations
- Water Capacity
- ?
- Holding Tank Capacity
- ?
- Headroom
- ?
- Cabins
- ?
Calculations
- Hull Speed
- 6.7 kn
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: 6.7 knots
- Sail Area/Displacement
- ?
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.
?
<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
- ?
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
?
<2: better suited for ocean passages
>2: better suited for coastal cruising
Notes
C CLASS CATAMARAN rule began with the creation of the International Catamaran Challenge Cup, first sponsored, in 1960, by the Sea Cliff Yacht Club, located in Long Island, NY USA. The event, loosely called the Little Americas Cup, continues to this day, although only intermittantly in recent years. Among development classes, it is recognized as one with the fewest restrictions. Boats that are built to the C Class rule are among the most advanced and fastest sailboats in the world for closed course racing.
Restrictions are as follows:
A crew of 2.
Maximum LOA is 25’.
Maximum Beam is 14’.
Maximum Sail Area is 300 sq feet. (For the past 20+ years, the sails have been multi element solid wings with varying methods of control)
There is no restriction on weight or design of foils.
The photo is of the US boat ‘Cogito’. Photo by Elizabeth B. Wrightson.
