Multihulled

Multihulled refers to vessels that have more than one hull. In maritime use, multihull boats are built from two or more separate hulls that are connected by a structural frame, deck, or other connecting elements. This arrangement contrasts with monohull boats, which rely on a single hull for buoyancy and stability.

The most common multihull configurations are catamarans, which have two hulls, and trimarans, which have three. Some designs extend to four or more hulls, though those are rare. The hulls are typically slender and separated, with a deck or platform spanning the gap. Sail rigs and propulsion systems may be shared across hulls or distributed to exploit the benefits of each hull.

Multihulls offer several potential advantages. They often provide greater initial stability due to the wide beam, increasing passenger comfort and reducing the likelihood of capsizing in rolling seas. The separated hulls can allow a larger open deck area and provide shallower draft for the same overall width, enabling access to shallow waters. In many configurations, the total wetted surface is reduced compared with a monohull of similar length, which can translate to improved speed potential under sail or efficient propulsion.

Disadvantages include higher construction and maintenance costs, more complex rigging and handling, and increased beam width that complicates docking and marina accommodations. Roughly handling and tuning can be required in heavy weather, and some multihull designs pose different stability challenges if severely trimmed or overloaded.

Historically, multihull vessels appear in traditional sailing cultures, notably Polynesian double-hulled canoes. In modern times, catamarans and trimarans have become common in recreational sailing, racing, and cruising, valued for their space, stability, and performance.