Design Brief & Intent 4
The core mission of the Searunner 25 was to provide a safe, ocean-capable cruising platform in a package that could easily be disassembled or folded for trailering. Jim Brown achieved this by defying the conventional layout of the era. Instead of the typical aft-cockpit configuration, the Searunner 25 features a central cockpit that splits the accommodations into separate forward and aft cabins. This layout serves a critical physical purpose: it places the crew’s weight and the primary payload directly in the center of buoyancy, dramatically reducing the hobby-horsing common in lightweight multihulls.
The interior design is intensely minimalist but clever. Because the main hull has a narrow waterline beam (measuring just under four feet at the gunwales), there is no room for a traditional saloon. Instead, the forward cabin houses a single or V-berth arrangement along with a creative head arrangement tucked under the bunk, while the aft cabin offers a separate nav-station, small galley area, and an additional single berth. Jim Brown designed the cabins with large, wrap-around plexiglass windows—often called "Cinerama" windows by owners—which bathe the small cabins in natural light and provide a dramatic view of the passing sea.
Variations & Configurations
While the fundamental hull shapes remained constant, the Searunner 25 was built in a few distinct structural configurations. The most popular is the folding version, which utilizes a heavy-duty stainless steel or aluminum A-frame hinge mechanism mounted on the crossbeams (or akas). This system allows the outer hulls (amas) to fold downward and inward, compressing the beam from over sixteen feet down to under eight feet for legal road trailering. Other builders opted for a "Tri-sectable" version, which allowed the floats and wing decks to be unbolted and disassembled entirely for seasonal maintenance or shipping, or a simpler, permanently fixed-wing version for those who did not require trailering.
The sail plan is traditionally a cutter rig, which is highly unusual for a twenty-five-foot vessel. Spreading the sail area across a mainsail, staysail, and jib keeps the center of effort low and manageable, offering exceptional flexibility in heavy weather. Early plans specified a wooden, box-section mast that owners could build themselves, though later iterations and subsequent refits almost exclusively feature aluminum spars. Underneath, the boat relies on a pivoting Western Red Cedar centerboard housed in a trunk beneath the cockpit floor, allowing the draft to range from a shallow sixteen inches with the board up to four and a half feet when fully extended.
Sailing Performance & Handling
The sailing dynamics of the Searunner 25 are shaped by its extremely low displacement and generous sail area. With a sail area to displacement ratio of 28.83, the boat is exceptionally powerful and responsive. In light air, where traditional monohulls struggle, the Searunner 25 accelerates rapidly, lifting its main hull and skating across the water on its narrow, low-drag amas. A displacement to length ratio of 90.78 places it firmly in the ultra-light category, indicating a hull form that surfs and planes with ease rather than pushing a heavy bow wave.
At the helm, the boat feels more like a high-performance dinghy than a cruising yacht, demanding active sail trim and quick reactions. Its capsize screening ratio of 4.89 must be interpreted through the lens of multihull physics; while a monohull of this rating would be deemed highly unstable, the trimaran’s wide sixteen-foot beam provides immense initial stability. However, because a trimaran cannot rely on a heavy lead keel to self-right, the safety of the vessel ultimately relies on the skipper's willingness to reef early. The motion in a seaway is quick and lively, as indicated by a comfort ratio of 3.88. It will not offer the slow, roll-damping motion of a heavy-displacement cruiser, but the central cockpit keeps the crew dry and isolated from the wildest motions of the bow and stern.
Market Snapshot & Economics
Because the Searunner 25 was primarily an owner-built design constructed from plans, there is no standardized production run or manufacturer pricing. On the brokerage market, these boats trade entirely on the quality of their construction, material choices, and current state of preservation. Professionally built examples—such as those produced by specialized composite yards in the 1970s—command a modest premium, but most transactions occur between enthusiasts who appreciate the design's unique history.
The economics of buying a Searunner 25 are heavily skewed toward refit costs rather than the initial purchase price. Because these are wood-and-epoxy structures, a neglected boat can be a financial black hole, requiring hundreds of hours of tedious labor to repair dry rot. Conversely, a well-maintained, epoxy-saturated example that has been stored under cover represents one of the most cost-effective ways to own a legitimate, ocean-capable multihull.
Known Issues & Triage
The primary threat to any Searunner 25 is moisture intrusion and subsequent plywood rot. Early hulls built in the late 1960s and 1970s were often sheathed in fiberglass using polyester resin, which does not bond well to wood over the long term and can trap water against the plywood. Modern buyers must thoroughly inspect the hull, decks, and particularly the underwing areas for soft spots, delamination, and water ingress.
The centerboard trunk and its pivot pin are another high-wear area. Because the centerboard is designed to kick up upon impact, the trunk is subjected to violent lateral loads when sailing hard to windward. Leaks along the trunk seams are common and difficult to repair without removing the cockpit floor. Additionally, the folding A-frame hinge mechanism should be checked for play or hairline cracks in the metal fabrications, as decades of trailering and high-load sailing can fatigue the weldments.
Modernization & Upgrades
Veteran owners of the Searunner 25 have found great success in modernizing the boat to enhance its safety and usability. Replacing the heavy, original stainless steel standing rigging with modern synthetic Dyneema or Colligo Marine lines significantly reduces weight aloft, which is highly beneficial on a light-displacement trimaran.
In the auxiliary department, the old, heavy two-stroke outboards are routinely replaced with lightweight, long-shaft four-stroke outboards—such as the Mercury Sail-Pro 5hp. Modern owners often install customized steering linkages (such as the EZ Steer system) that connect the outboard directly to the kick-up rudder, allowing for effortless maneuvering in tight marina spaces. On the electrical side, the absence of an inboard alternator makes the Searunner 25 an ideal candidate for high-efficiency solar arrays mounted on articulating brackets, feeding small lithium iron phosphate (LiFePO4) battery banks that run modern GPS, AIS, and LED lighting systems with minimal weight penalties.
The Verdict
The Searunner 25 is a brilliant, highly specialized trimaran that offers unmatched performance and seaworthiness for its length. It is not a boat for those who demand dockside luxury or standing headroom, but for the purist sailor who wants a fast, trailerable, and proven pocket voyager, Jim Brown's design remains an icon of multihull engineering.
Pros:
- Exceptional sailing performance and speed, particularly in light to moderate air.
- Highly seaworthy central-cockpit design that prioritizes crew safety and limits hobby-horsing.
- Cutter rig configuration offers highly versatile sail-handling options in variable weather.
- Folding and demountable options allow for easy trailering and off-season storage.
- Extremely shallow draft with the centerboard up, allowing for easy beaching and gunkholing.
Cons:
- Amateur-built plywood construction requires rigorous survey and constant vigilance against rot.
- Highly restricted interior space with no standing headroom and divided, separated cabins.
- Motion in a seaway is active and quick, which may cause fatigue on long passages.
- Folding or unfolding the boat for trailering is a labor-intensive process that typically requires a full day.
