Design and Origins
The hull form traces back to a Herreshoff 18-foot tender, lengthened by the designers to reach the 21-foot LOA and 19-foot waterline we see today anchor. Where most shallow-draft sailboats reach for a centerboard, the Sea Pearl instead uses leeboards, paired with a kick-up rudder that lets the stern ride up over mud and sand without damage anchor. That leeboard choice was not cosmetic: by eliminating the centerboard trunk, the forward area of the cockpit was freed for seating or overnight use, a layout consequence unique to this boat anchor. The Tri and Tri-Sport trimaran variants share the 14-foot beam and 950-pound displacement of the spec record, with a centerboard rather than leeboards, and trailering weight climbing to roughly 1000–1500 pounds against the monohull's 600 anchor.
Construction
The hull is hand-laid fiberglass cloth over Corecell foam, with no wood in the structure to rot, and it includes an integral deck and liner anchor. Ballast is provided by easily filled and emptied tanks set under the deck, a system that lets the owner tune righting moment for trailering or sailing without permanent lead anchor. The capsize screening ratio of 5.7 and comfort ratio of 2.23 place the boat firmly in the small-trailerable expedition category rather than the offshore cruiser class.
Rig and Handling
The boat carries twin masts in an unstayed cat-ketch rig, a configuration that keeps the spars short enough to sit on deck with no fore or aft overhang when stepped anchor. The sails furl directly around the masts, and the masts themselves are easily stepped, so the boat can be rigged or stowed by a short-handed crew without a crane anchor. At 166 square feet of sail in the trimaran's recorded plan and a hull speed near 5.84 knots, the design is light enough to be pushed at a useful pace by a small outboard or even rowed if the wind fails anchor. The Tri draws only 0.67 feet with boards up and reaches 2.67 feet with the centerboard down, preserving the shallow-water brief.
Accommodations
Without a centerboard trunk intruding, the forward cockpit becomes an excellent family seating area or a place to sleep, and the optional cabin top or bimini turns that space into weather protection for overnight stops anchor. In the single-hull version the central cockpit runs ten feet and the aft cockpit measures six feet six, figures that reveal an open-plan ethos more than enclosed cabin room. The simple design and low maintenance are what make the model a credible small expedition boat, and owners have taken Sea Pearls around Patagonia, across the Caribbean, and up the Danube anchor.
Ownership Notes
Marine Concepts offered the boat in custom configurations — mono, Tri, and Tri-Sport — and the builder claimed a custom order could be completed and delivered in six weeks anchor. The manufacturer also claimed well over 500 monohull Sea Pearls were on the water, a figure that sits above the 415 hulls recorded in the database for the broader model line anchor.
The Verdict
The Tri Sea Pearl 21 is a specialist's boat: brilliant where the water is thin and the launch ramp is home, less compelling as a conventional coastal cruiser. Its leeboard-and-kick-up-rudder solution on the monohull, unstayed twin-mast rig, and trunkless forward cockpit make it a genuine shallow-water tool with a proven expedition pedigree.
Pros
- Six-inch draft with boards up opens waters closed to most sailboats
- Trunkless forward cockpit gives rare open sleeping or seating space
- Unstayed cat-ketch rig with mast-furling sails simplifies short-handed handling
- Corecell/fiberglass hull with no wood avoids rot and eases upkeep
Cons
- Light 950-pound displacement and 5.7 capsize ratio limit offshore ambition
- Ballast tanks require active management versus fixed ballast
- Trimaran trailering weight of 1000–1500 pounds demands a larger vehicle
