Trailertri 18 Information, Review, Specs

Sailing Performance & Handling

The Trailertri 18 is defined by its impressive power-to-weight ratio and its ability to plane in conditions where monohulls of similar length remain trapped by their hull speed. With a displacement of approximately 1,698 pounds and a sail area of roughly 156 square feet, the boat carries a Sail Area/Displacement ratio of 17.58, which provides responsive acceleration in light air. Because it relies on its beam for stability rather than a heavy lead keel, the boat sails at very low heel angles, typically no more than 10 to 15 degrees, offering a "level" sailing experience that is less fatiguing for crews.

Handling is generally characterized as nimble, though the boat requires specific techniques when maneuvering under power. According to designer Ian Farrier, the central daggerboard provides excellent tracking while sailing, but the boat can be prone to significant sideways drift when the board is raised or when the boat is motoring in its folded configuration. This makes slow-speed maneuvering in crowded marinas a learned skill. Under sail, the boat’s sea-kindliness is noted for its ability to "skirt" over waves rather than punching through them, though the relatively small volume of the original amas means that over-canvassing in heavy gusts should be avoided to prevent burying the leeward float.

Interior Comfort & Variations

For an 18-foot boat, the Trailertri 18 offers a surprisingly functional "micro-cruiser" interior. The layout was a significant improvement over the 1974 prototype, with Farrier claiming the production plans offered 50% more internal volume. The cabin typically features a V-berth for two adults and limited storage beneath the cockpit and bunks. Because most examples were built from plans by amateurs, interior finishes vary wildly, ranging from utilitarian painted plywood to high-end timber veneers.

The success of the 18-foot hull led directly to the development of its larger siblings, which are often discussed in the same technical circles. The Trailertri 680 and the later 720 models utilized the same fundamental folding geometry but offered extended transoms and significantly more interior headroom. While the 18 is a true daysailer with "overnighting" capability, these larger variants moved toward legitimate coastal cruising.

Popular Mentions & Media

The Trailertri 18 is frequently cited in multihull literature as the design that "saved" the trimaran in Australia and North America. In the 1970s, multihulls were often criticized for safety issues, but the Trailertri series established such a strong track record for stability that they became the only trimarans insurable in Australia for a period. This design eventually led to the creation of the Corsair F-27, which was inducted into the American Sailboat Hall of Fame, a lineage that begins directly with the Trailertri 18.

Known Issues & Buyer’s Checklist

As a primarily owner-built plywood vessel, the condition of a Trailertri 18 is entirely dependent on the skill of the original builder and the quality of the epoxy encapsulation.

• Plywood Rot: The most critical inspection point is the integrity of the plywood, particularly in the "tortured ply" curves of the hull and the areas around the folding strut attachments. Soft spots in the deck or near the waterline often indicate freshwater ingress that has bypassed the fiberglass skin.
• Folding Hardware: While the folding system is over-engineered and famously durable, the aluminum struts and stainless steel pivot bolts should be checked for galvanic corrosion or "slop" in the bushings.
• Centerboard Trunk: The trunk is a common site for leaks. Inspect the internal lamination for cracks, especially if the boat has a history of hard groundings.
• Trampoline Nets: The "nets" between the main hull and amas are structural safety features. On older boats, these are often UV-degraded and may require replacement with modern Dyneema or high-strength PVC mesh.

Community & Resources

The primary hub for technical data and historical documentation is the Multihull Yacht Club Queensland (MYCQ), which maintains an archive of the Trailertri Club's history. Although Ian Farrier passed away in 2017 and official plans are no longer sold for new builds, several active Farrier-design forums provide peer-to-peer support for owners undertaking restorations of these classic plywood flyers.

The Verdict

The Trailertri 18 is a vintage high-performance gem for sailors who value speed and trailability over cabin headroom.

Pros:

• Exceptional Trailability: Can be rigged and launched by one person faster than almost any other trimaran in its class.
• High Performance: Capable of double-digit speeds in moderate breezes.
• Stability: Offers a stable, flat sailing platform that is ideal for introducing nervous sailors to the water.

Cons:

• Maintenance Intensive: As a plywood/epoxy boat, it requires more diligent "dry" storage and inspection than a modern GRP production boat.
• Cramped Quarters: The interior is best suited for gear storage or "camping style" overnighting rather than extended cruising.
• Low Freeboard: In choppy conditions, the ride can be quite wet for those in the cockpit.