Chassiron GC — Information, Review, Specs

Michel Joubert·1974 – 1984·~120 hulls·E. Richard
Approximate drawing

Hover a measurement to read its value

Hull type
Monohull · full
Rig
Ketch
LOA
34.28' · 10.45 m
Displ.
12,677 lbs · 5,750 kg
First year
1974

The Chassiron GC (Grande Croisière) is a hallmark of the French "transitional" era of boatbuilding, a period where fiberglass hulls were first mated with the heavy, traditional woodwork of established shipyards. Built by the Chantier Richard yard in Marennes, France, the GC was produced primarily between 1968 and 1984, with roughly 120 to 200 units completed. Designed by Michel Joubert, the GC was intended as a robust, bluewater cruiser capable of longdistance passagemaking with a level of seakindliness that remains highly regarded in the used market. The boat’s silhouette is instantly recognizable by its classic lines, which often include a ketch rig and a significant amount of exterior timber, reflecting the builder’s history as a wooden boat specialist. Detailed historical notes and photographs of the yard can be found via the Voiliers Bois Chassiron archive.

Measurements

Dimensions 01

LOA
34.28 ft
LWL
28.05 ft
Beam
9.45 ft
Draft
5.02 ft
Max headroom
-
Air draft
41.01 ft

Construction & hull 02

Construction
Fiberglass
Hull type
Monohull
Keel type
Full
Rudder
1× Attached
Ballast
4409 lbs
Displacement
12677 lbs
Water
-
Fuel
-

Rig & sails 03

Rig type
Ketch
P · main luff
-
E · main foot
-
I · fore ht.
-
J · fore base
-
Forestay (est)
-
Sail area
564.24 sqft

Calculations 04

SA/D ratio
16.6
Ballast/Disp.
34.78
D/L ratio
256.43
Comfort ratio
32.87
Capsize screening
1.62
Hull speed
7.1 kn

Sailing Performance & Handling

The Chassiron GC is a heavy-displacement cruiser that prioritizes stability and tracking over raw speed or agility. With a Displacement/Length (D/L) ratio of approximately 256, it sits firmly in the category of moderate-to-heavy offshore cruisers. This weight, combined with a full long keel and a ballast ratio of 35%, provides a Motion Comfort Ratio of 32.7, indicating a vessel that remains relatively stable and predictable in choppy or heavy seas. Owners frequently report that the boat "finds its groove" in a stiff breeze, where the weight helps it punch through waves rather than being tossed over them.

The masthead ketch rig is the most common configuration, offering a versatile sail plan that is easily managed by a small crew. In heavy weather, the GC can be sailed under "jib and jigger"—using only the headsail and the mizzen—to maintain balance and control while minimizing heel. While it is not a "pointer" and struggles to maintain high speeds close-hauled compared to modern fin-keel designs, its directional stability is exceptional. This makes it a preferred choice for long reaches where the boat can track for hours with minimal helm correction. However, the long keel makes maneuvering in tight Mediterranean-style marinas a challenge, often requiring a skilled hand or the addition of a bow thruster in refitted models.

Interior Comfort & Variations

The interior of the Chassiron GC is characterized by a "no-plastic" aesthetic, with the French yard utilizing high-quality iroko and mahogany for the bulkheads and cabinetry. The layout typically features a forward V-berth, a main salon with a convertible dinette, and a sea-berth, providing total accommodation for five. Headroom is generous for a boat of this vintage, often exceeding 6'2" (1.90m) in the main cabin, which enhances the sense of space on what is a relatively narrow 9.45-foot beam.

Several siblings were built on similar design philosophies at Chantier Richard. The Chassiron CF (Charentais-Finistère) served as a smaller, 30-foot entry, while the Chassiron TDM (Tour du Monde) offered a more rugged, globetrotting variation. Later in the production run, the yard introduced the Chassiron RF (Richard-Fatovitch), which featured updated underwater lines and more modern GRP superstructures to reduce maintenance while keeping the classic hull shape. According to records at Patrimoine Maritime et Fluvial, the RF was a direct evolution of the GC designed to modernize the brand's performance.

The Chassiron GC secured its place in French maritime history through the exploits of Brigitte Oudry. In 1978, Oudry completed a solo circumnavigation via the three great caps aboard her Chassiron GC, named Géa. This voyage proved the model's offshore credentials and solidified its reputation as a serious long-distance cruiser. Technical data and specific model history can be referenced through the Ouest-atlantis database.

Known Issues & Buyer’s Checklist

Prospective buyers should approach the Chassiron GC with a focus on structural maintenance, as these boats are now reaching half a century of age.

  • Teak Deck Condition: Many GC models were built with teak decks screwed directly into a fiberglass-cored subdeck. Over decades, these screws can allow water to penetrate the core, leading to delamination. A thorough moisture meter test and "tapping" of the deck are essential.
  • Chainplates and Rigging: Given the boat's age and blue-water intent, the original stainless steel chainplates and the ketch rigging should be inspected for crevice corrosion, especially where they pass through the deck.
  • Engine Access and Age: Original engines were often underpowered by modern standards (approx. 25-30 HP). While many have been repowered with Yanmar or Volvo Penta units, buyers should check the engine mounts and exhaust risers, as the engine compartments can be cramped.
  • Wood-to-Hull Joints: The heavy wooden coachroof and cockpit are bolted to the GRP hull. These joints can leak if the bedding compound has dried out, leading to interior rot in the bulkheads.

Community & Resources

The Chassiron community is primarily centered in France, with a dedicated following in the Charente-Maritime region where they were built. The most active group is the Association des Propriétaires de Chassiron, which maintains a presence on the "Hisse et Oh" forum and through the "Voiliers Bois Chassiron" blog. These groups are invaluable for sourcing specific hardware or technical drawings for the various Joubert-designed iterations.

The Verdict

The Chassiron GC is a "yacht of yesteryear" that offers a level of character and seaworthiness rarely found in modern production boats of similar length. It is a vessel for the traditionalist who values a comfortable motion at sea over a fast time around the buoys.

  • Pros:
    • Exceptional sea-kindliness and heavy-weather stability.
    • Beautiful classic aesthetic with high-quality interior woodwork.
    • Proven blue-water pedigree with documented solo circumnavigations.
    • Easily managed ketch rig for short-handed cruising.
  • Cons:
    • High maintenance requirements for exterior teak and wood trim.
    • Poor maneuverability in tight quarters due to the long keel.
    • Slow performance in light winds and limited upwind pointing ability.
    • Vulnerable to deck core moisture issues in poorly maintained examples.

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