Design Brief & Intent
The As de Trèfle was designed with a clear mandate: maximize interior volume, structural simplicity, and safety within a highly compact footprint. During an era when fiberglass was still in its infancy and premium solid-timber yachts were prohibitively expensive, Herbulot’s hard-chined plywood hulls offered a brilliant alternative. The flat panels of marine plywood could be quickly assembled over a framework of oak frames and chine logs, allowing CMN to produce the boat efficiently while also offering the design to amateur builders.
Inside, the boat features a remarkably minimalist layout that reflects its utilitarian roots. Given the hull length of 6.30 meters, the headroom is understandably modest, but Herbulot maximized the usable space. The traditional layout comprises a basic V-berth forward, two flanking settee berths in the main cabin, and a highly simplified galley area. The joinery is honest and functional, relying on painted plywood and exposed timber frames rather than heavy, dark teak veneers. It was a cabin designed for active sailors who prioritized simplicity, breeze, and a dry place to sleep after a long day on the water.
Sailing Performance & Handling
Under sail, the As de Trèfle is a lively and surprisingly stiff performer. Boasting an exceptionally high ballast-to-displacement ratio of 45.01 percent, the boat carries 794 pounds of its 1,764-pound total weight in its deep fin keel. This massive righting moment makes the pocket cruiser remarkably stable in a blow, standing up to its canvas far longer than comparable micro-cruisers of its era.
The sailboat’s performance in light-to-moderate air is highly competitive, thanks to a potent fractional sloop rig. With a sail area-to-displacement ratio of 24.55, the As de Trèfle has plenty of power relative to its weight, enabling it to accelerate rapidly and slip through the water with ease. This light-displacement character is confirmed by its displacement-to-length ratio of 134.13, indicating a hull that is highly responsive at the helm and quick to find its stride.
However, its physical scale presents inherent limitations. With a low comfort ratio of 10.4, the As de Trèfle will have a quick, active motion in a seaway, translating waves directly to the crew's physical experience. Additionally, its capsize screening ratio of 2.39 indicates that while highly stable for coastal day-sailing, it does not possess the self-righting margins required for serious offshore operations. It is a nearshore thoroughbred, designed to tackle coastal chop and tidal estuaries with agility.
Known Issues & Triage
As a vintage wooden vessel built in the 1960s, the primary adversary of any surviving As de Trèfle is freshwater rot and structural decay. Plywood hulls of this vintage are highly susceptible to rot along the chine logs, transom boundaries, and the stem. Buyers must carefully inspect the bilge areas, looking for soft wood, dark water staining, or delamination of the plywood plys.
The deck-to-hull joint and the cabin trunk corners are also notorious areas for water ingress. Because these boats were often built using traditional brass screws, copper rivets, and early marine adhesives, decades of flexing can cause joint degradation. Additionally, the fin keel join is a critical structural triage point; the keel bolts and the internal wooden backing blocks must be closely examined for signs of rust, weeping, or structural compression of the wood surrounding the keel floor.
Modernization & Upgrades
Modern owners of the As de Trèfle have successfully preserved these historic pocket cruisers by embracing modern materials. The most common structural upgrade is a complete exterior strip-to-wood refit followed by a glass-and-epoxy encapsulation (such as the West System). Wrapping the vintage plywood hull in lightweight fiberglass cloth saturated with epoxy resin seals the timber from moisture, drastically reduces maintenance, and adds modern puncture resistance.
On the mechanical side, the boat is ideally suited for modern auxiliary power upgrades. Because it was designed for small outboards, veteran owners are increasingly replacing heavy, noisy two-stroke outboards with clean, silent electric outboards. Brands like Torqeedo or ePropulsion match the boat's lightweight ethos perfectly. This shift is typically paired with a simplified electrical overhaul, installing a single 100Ah lithium iron phosphate (LiFePO4) battery and a small, deck-mounted solar panel to power basic navigation electronics, LED cabin lights, and mobile devices.
The Verdict 2
The As de Trèfle remains a charming testament to the golden era of French naval architecture. For the classic yacht enthusiast or the budget-conscious sailor who enjoys working with wood, this 20-footer offers an incredibly rewarding, tactile sailing experience marked by excellent light-wind performance and robust safety margins.
Pros
- High ballast ratio of 45.01% provides excellent stability and stiffness in breezy conditions.
- Lively fractional rig and light displacement yield superb light-air performance.
- Intrinsic historical appeal as a classic Jean-Jacques Herbulot design built by CMN 2.
- Easily trailered and ramp-launched due to its compact dimensions and light weight.
Cons
- Plywood construction requires fastidious, ongoing maintenance to prevent rot and delamination.
- Low comfort ratio of 10.4 results in a quick, motion-heavy ride in open-water chop.
- Highly minimalist interior accommodations offer very limited headroom and comfort.
- High capsize screening ratio of 2.39 restricts its safe operational envelope strictly to coastal and inland waters.
