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.
Alvin (DSV-2) is a crewed deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts. The vehicle was built by General Mills' Electronics Group in Minneapolis, Minnesota. Named to honor the prime mover and creative inspiration for the vehicle, Allyn Vine, Alvin was commissioned on June 5, 1964. The submersible is launched from the deep submergence support vessel RV Atlantis (AGOR-25), which is also owned by the U.S. Navy and operated by WHOI. The submersible has made more than 5,000 dives, carrying two scientists and a pilot, to observe the lifeforms that must cope with super-pressures and move about in total darkness, as well as exploring the wreck of Titanic. Research conducted by Alvin has been featured in nearly 2,000 scientific papers.
A catamaran is a watercraft with two parallel hulls of equal size. The distance between a catamaran's hulls imparts resistance to rolling and overturning. 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.
Skjold-class corvettes are a class of six light, superfast, stealth missile corvettes in service with the Royal Norwegian Navy. The boats were formerly classed as MTBs but, from 2009, the Royal Norwegian Navy has described them as corvettes (korvett) because their seaworthiness is seen as comparable to corvettes, and because they do not carry torpedoes. They were built at the Umoe Mandal yard. With a maximum speed of 55 knots (102 km/h), the Skjold-class corvettes were the fastest combat ships afloat at the time of their introduction.
A deep-submergence vehicle (DSV) is a deep-diving crewed submersible that is self-propelled. Several navies operate vehicles that can be accurately described as DSVs. DSVs are commonly divided into two types: research DSVs, which are used for exploration and surveying, and DSRVs, which are intended to be used for rescuing the crew of a sunken navy submarine, clandestine (espionage) missions, or both. DSRVs are equipped with docking chambers to allow personnel ingress and egress via a manhole.
Sea Shadow (IX-529) was an experimental stealth ship built by Lockheed for the United States Navy to determine how a low radar profile might be achieved and to test high stability hull configurations that have been used in oceanographic ships.
A stealth ship is a ship that employs stealth technology construction techniques in an effort to make it harder to detect by one or more of radar, visual, sonar, and infrared methods.
The M80 Stiletto is an American prototype naval ship using advanced stealth technologies. The M80 was designed by the M Ship Company then built by Knight and Carver, as an experimental testbed ship for The Pentagon’s Office of Force Transformation. It is notable for its innovative pentamaran hull design and advanced carbon fiber composite construction.
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.
The AN/UQQ-2 Surveillance Towed Array Sensor System (SURTASS), colloquially referred to as the ship's "Tail", is a towed array sonar system of the United States Navy.
USNS Indomitable (T-AGOS-7) was a United States Navy Stalwart-class ocean surveillance ship in service from 1985 to 2002. From 2003 until 18 June 2014, she was in commission in the National Oceanic and Atmospheric Administration (NOAA) as the oceanographic research ship NOAAS McArthur II. As of 2018 it serves as a mother ship now named the Deep Submersible Support Vessel (DSSV) Pressure Drop for the crewed deep-ocean research submersible DSV Limiting Factor.
HSV Sea Slice was an experimental vessel, built by Lockheed Martin, for the United States Navy, later used in commercial service.
RV Kilo Moana (AGOR-26) is a small waterplane area twin hull (SWATH) oceanographic research ship owned by the US Navy and operated by the University of Hawaii as a part of the University-National Oceanographic Laboratory System (UNOLS) fleet. She was designed to operate in coastal and blue water areas. The unique SWATH hull-form provides a comfortable, stable platform in high sea conditions.
USNS Victorious (T-AGOS-19) is a Victorious-class ocean surveillance ship which was acquired by the U.S. Navy in 1991 and assigned to the Military Sealift Command (MSC) Special Missions Program.
In ship design, an inverted bow is a ship's or large boat's bow whose farthest forward point is not at the top. The result may somewhat resemble a submarine's bow. Inverted bows maximize the length of waterline and hence the hull speed, and have often better hydrodynamic drag than ordinary bows. On the other hand, they have very little reserve buoyancy and tend to dive under waves instead of piercing or going over them.
Duplus was a diving support and sample drilling ship for the petrol industry. She was designed and built for use in the North Sea towards the end of the 1960s. Most probably, she was the world's first ship built to the SWATH design principle. After two years of trials and initial use, she was rebuilt into a hybrid form between SWATH ship and catamaran.
A semi-submersible naval vessel is a hybrid warship, that combines the properties of a surface ship and submarine by using water ballast to partially immerse and minimize its above-waterline profile, thereby improving its stealth characteristics when in hostile waters. The USS Monitor was an antecedent to such craft with its low-profile deck and gun turret. Russian and North Korean semi-submersible naval vessels evolved from torpedo boats and special forces boats that could partially submerge to perform their missions. The US Navy SEALs use such vessels for clandestine special forces actions. Efforts to embody advantageous surface-ship characteristics into submarines have not been widely adopted.
The Hibiki-class ocean surveillance ship is a class of surveillance ships operated by the Japan Maritime Self-Defense Force. The ships have a small-waterplane-area twin hull (SWATH) design.
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.
