trimarans

A trimaran is a multihull boat or ship configuration that uses three parallel hulls: a central main hull and two smaller outriggers, called amas, located on either side. The amas are connected to the main hull by horizontal beams or trusses, creating a wide overall beam while keeping the wetted surface area relatively low. This arrangement provides increased stability, more deck space, and the potential for higher speeds compared to many monohulls and some other multihulls.

Design and construction vary, but most trimarans share a few common features. The main hull typically carries the cockpit, cabin, and primary rigging, while the amas support the rig and contribute to buoyancy. The beams or trusses can be rigid or articulated, and some modern designs incorporate hydrofoils to lift the amas or the entire hull at speed, further reducing drag. Materials range from traditional wood and plywood to fiberglass, composites, and advanced polymers in contemporary racing and cruising models.

Performance characteristics often include exceptional stability at rest and in waves, a broad working platform, and the potential for high speeds, especially when sails are efficiently balanced and hydrofoils are employed. Trimarans can be more challenging to maneuver in tight spaces and at very low speeds due to their wide beam and greater sail area, but their speed and efficiency make them popular for offshore cruising and multihull racing.

History and usage span traditional voyaging canoes in the Pacific to modern racing and cruising craft. The three-hull concept remains distinct from catamarans, which have two hulls, and monohulls, which have one.