BoatsCNSO Shellfish

CNSO Shellfish

Masthead Sloop · Fin With Rudder On Skeg · First built 1965

A versatile masthead sloop available in ketch configuration, featuring a shallow 1-metre draft for exploring shoal waters

Designed by Francois Sergent.

LOA
Beam
Draft (max)
Displacement
Ballast
Hull type
Fin With Rudder On Skeg

Is it for you?

Character

Where this design lands on the numbers a shopper trusts — read straight from her own ratios.

LivelySea-kindly

Her light displacement on a narrow beam gives 18 — a quick, lively motion that feels every wave.

Comfort ratio 18
CoastalBluewater

1.94 — just under the 2.0 offshore line; her beam is modest for her weight.

Capsize screening 1.94
LightHeavy

151 — light for her waterline, so she is easily driven and quick to accelerate.

Displacement / length 151
EasygoingPowered-up

19.3 — plenty of sail for her weight; lively and quick to respond.

Sail area / displacement 19.3
TenderStiff

36% of her weight is ballast — moderately stiff, a middle-of-the-road stability.

Ballast 36%

Light and lively — happiest day-sailing and coastal-hopping in settled weather.

  • Narrower than ~83% of boats her size on file

Compared with 2258 boats of the same type within a quarter of her length.

The record

Full specifications

The complete reference set — tap any figure to switch between metric and imperial.

Dimensions
Weights
Ballast / displacement
36.4%
Rig & sail area
Rig
Masthead Sloop
Ratios
SA / displacement
19.3
Displacement / length
151.3
Comfort ratio
17.7
Capsize screening
1.94
Hull speed
6.6 kn
Pounds / inch immersion
711
Hull
Hull type
Fin with rudder on skeg
Construction
Wood
Ballast type
Cast Iron
Production
Years built
First built 1965
Designer
Francois Sergent
Builder
CNSO

Boats like this, on the water

Nobody has filmed this one — but these are close.

Comparable boats the fleet has on camera: same type, within a quarter of her length. Open the boat, or watch the video — a timestamp means she only appears in passing.

J/29 FR8.99 mSame hull family0.2 m longerA 1982-1987 fractional sloop featuring a transom-hung rudder and a high 23.35 SA/displacement ratio for speed
Pogo 8.508.50 mSame hull family0.3 m shorterA high-performance fractional sloop by Pierre Rolland featuring a wide beam and dual rudders for rapid offshore sailing
J Boats J/98.52 mSame hull family0.2 m shorterA 2021-launched daysailer with a 24.13 sail-area-to-displacement ratio, built for rapid, responsive performance
Jeanneau Aquila 278.70 mSame hull familyNear-identical lengthA Philippe H. Harle-designed masthead sloop offered in both standard and deep-keel Regatta configurations
Sunbeam 298.95 mSame hull family0.2 m longerA Schoechl-designed masthead sloop with a high sail area-to-displacement ratio, built for performance over two decades
Maxi Yachts Fenix 8.58.50 mSame hull family0.3 m shorterA 1980s cruiser with a 1.5-metre bulb keel and spade rudder, designed for a balanced, stable coastal experience

The family

Related models

The designs closest to hers — usually the rest of the builder's range, sometimes the same hull sold under another name.

Keep looking

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