A multihull is a boat or ship with more than one hull, whereas a vessel with a single hull is a monohull. The most common multihulls are catamarans, and trimarans. There are other types, with four or more hulls, but such examples are very rare and tend to be specialised for particular functions.
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity and purpose. Ships have supported exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to world population growth. Ship transport is responsible for the largest portion of world commerce.
A yacht is a sailing or power vessel used for pleasure, cruising, or racing. There is no standard definition, though the term generally applies to vessels with a cabin intended for overnight use. To be termed a yacht, as opposed to a boat, such a pleasure vessel is likely to be at least 33 feet (10 m) in length and may have been judged to have good aesthetic qualities.
A catamaran is a multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stabilized craft, deriving its stability from its wide beam, rather than from a ballasted keel as with a monohull boat. Catamarans typically have less hull volume, smaller displacement, and shallower draft (draught) than monohulls of comparable length. The two hulls combined also often have a smaller hydrodynamic resistance than comparable monohulls, requiring less propulsive power from either sails or motors. The catamaran's wider stance on the water can reduce both heeling and wave-induced motion, as compared with a monohull, and can give reduced wakes.
A trimaran is a multihull boat that comprises a main hull and two smaller outrigger hulls which are attached to the main hull with lateral beams. Most modern trimarans are sailing yachts designed for recreation or racing; others are ferries or warships. They originated from the traditional double-outrigger hulls of the Austronesian cultures of Maritime Southeast Asia; particularly in the Philippines and Eastern Indonesia, where it remains the dominant hull design of traditional fishing boats. Double-outriggers are derived from the older catamaran and single-outrigger boat designs.
A fishing trawler is a commercial fishing vessel designed to operate fishing trawls. Trawling is a method of fishing that involves actively dragging or pulling a trawl through the water behind one or more trawlers. Trawls are fishing nets that are pulled along the bottom of the sea or in midwater at a specified depth. A trawler may also operate two or more trawl nets simultaneously.
Outrigger boats are various watercraft featuring one or more lateral support floats known as outriggers, which are fastened to one or both sides of the main hull. They can range from small dugout canoes to large plank-built vessels. Outrigger boats can also vary in their configuration, from the ancestral double-hull configuration (catamarans), to single-outrigger vessels prevalent in the Pacific Islands and Madagascar, to the double-outrigger vessels (trimarans) prevalent in Island Southeast Asia. They are traditionally fitted with Austronesian sails, like the crab claw sails and tanja sails, but in modern times are often fitted with petrol engines.
Proas are various types of multi-hull outrigger sailboats of the Austronesian peoples. The terms were used for native Austronesian ships in European records during the Colonial era indiscriminately, and thus can confusingly refer to the double-ended single-outrigger boats of Oceania, the double-outrigger boats of Island Southeast Asia, and sometimes ships with no outriggers or sails at all.
A small waterplane area twin hull, better known by the acronym SWATH, is a catamaran design that minimizes hull cross section area at the sea's surface. Minimizing the ship's volume near the surface area of the sea, where wave energy is located, minimizes a vessel's response to sea state, even in high seas and at high speeds. The bulk of the displacement necessary to keep the ship afloat is located beneath the waves, where it is less affected by wave action. Wave excitation drops exponentially as depth increases, so wave action normally does not affect a submerged submarine at all. Placing the majority of a ship's displacement under the waves is similar in concept to creating a ship that rides atop twin submarines.
Incat Tasmania is an Australian manufacturer of high-speed craft (HSC) catamaran ferries. Its greatest success has been with large, sea going passenger and vehicle ferries, but it has also built military transports and since 2015 it has built smaller river and bay ferries. Based in Derwent Park, a suburb of Hobart, Tasmania, Australia, it was founded by Bob Clifford.
The Arun-class lifeboat was a fast all-weather lifeboat designed by the Royal National Lifeboat Institution (RNLI) for service at its stations around the coasts of the United Kingdom and Ireland. They were operated by the RNLI between 1971 and 2008. Many have been sold to see further service in the lifeboat and coastguard services of other countries.
A wave-piercing boat hull has a very fine bow, with reduced buoyancy in the forward portions. When a wave is encountered, the lack of buoyancy means the hull pierces through the water rather than riding over the top, resulting in a smoother ride than traditional designs, and in diminished mechanical stress on the vessel. It also reduces a boat's wave-making resistance.
118 WallyPower, christened Galeocerdo, is a 118-foot (36 m) luxury motor yacht with a maximum speed of 60 knots, produced by Wally Yachts. The yacht is narrow and angular in design with black glass housing, driven by three Vericor TF50 gas turbines generating 5,600 horsepower (4,200 kW), each driving a Rolls-Royce Kamewa water jet, two steerable outboard and a non-steering booster on the centerline. The steerable water jets also have a diesel engine input for a 370 hp (280 kW) Cummins diesel, thus making the ship a combined diesel or gas turbine (CODOG) configured vessel. The total power output is 16,800 horsepower (12,500 kW). One 118 WallyPower has been constructed. It is owned by the Kondakji family and cost £14m.
The Type 22 missile boat is a ship class in the Chinese People's Liberation Army Navy. The first boat was launched in April 2004 by the Hudong-Zhonghua Shipyard at Shanghai. The boats incorporate stealth features and are based on Australian-designed wave-piercing catamaran hulls that are more stable than other fast missile craft in high sea conditions. 82 of these missile boats are currently in service with three flotillas having been produced over a span of seven years, operating in squadrons of eight vessels each.
A sailing yacht, is a leisure craft that uses sails as its primary means of propulsion. A yacht may be a sail or power vessel used for pleasure, cruising, or racing. There is no standard definition, so the term applies here to sailing vessels that have a cabin with amenities that accommodate overnight use. To be termed a "yacht", as opposed to a "boat", such a vessel is likely to be at least 33 feet (10 m) in length and have been judged to have good aesthetic qualities. Sailboats that do not accommodate overnight use or are smaller than 30 feet (9.1 m) are not universally called yachts. Sailing yachts in excess of 130 feet (40 m) are generally considered to be superyachts.
An aerodynamically alleviated marine vehicle (AAMV) is a high speed marine vehicle configuration that uses aerodynamically generated forces (lift) to 'alleviate' its weight. The advantage is that the hydrodynamic lift required to sustain the weight of the vehicle is diminished, leading to a diminished hydrodynamic drag. The vehicle is in constant contact with the water, therefore the aerodynamic surfaces operate in ground effect. The name derives from the "Aerodynamic Alleviation Concept", presented by L.J. Doctors to illustrate the positive effect of using a wing-like superstructure on a catamaran configuration.
LOMOcean Marine is a naval architecture and yacht design company based in Auckland, New Zealand.
The Makar-class survey catamarans are a series of six 500 ton steel hull/aluminium superstructure Hydrographic Survey Catamarans being built by Alcock Ashdown (Gujarat) Ltd at its Bhavnagar shipyard for the Indian Navy. The ships are designed by an Australian naval architecture firm Sea Transport Solutions, which is based on Queensland's Gold Coast. The deal was canceled due to the extensive delays as the Navy was not satisfied with the timeline and a fresh award for construction of another class of survey vessels to the GRSE has also been undertaken.
Polynesian multihull terminology, such as "ama", "aka" and "vaka" are multihull terms that have been widely adopted beyond the South Pacific where these terms originated. This Polynesian terminology is in common use in the Americas and the Pacific but is almost unknown in Europe, where the Anglo-Saxon terms "hull" and "outrigger" form normal parlance. Outriggers, catamarans, and outrigger boats are a common heritage of all Austronesian peoples and predate the Micronesian and Polynesian expansion into the Pacific. They are also the dominant forms of traditional ships in Island Southeast Asian and Malagasy Austronesian cultures, where local terms are used.
A high-aspect-ratio twin-hull vessel refers to a certain design of catamaran vessels with small waterplane area. These vessels are built and used by the Islamic Revolutionary Guard Corps (IRGC) of Iran. Such design is considered relatively rare in military usage.
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