Small Waterplane Area Twin Hull
Encyclopedia
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
cross section area at the sea's surface. Minimizing the ship's volume near the surface area of the sea
Sea
A sea generally refers to a large body of salt water, but the term is used in other contexts as well. Most commonly, it means a large expanse of saline water connected with an ocean, and is commonly used as a synonym for ocean...
, where wave
Wave
In physics, a wave is a disturbance that travels through space and time, accompanied by the transfer of energy.Waves travel and the wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass...
energy is located, maximizes a vessel's stability, 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 (Deeply submerged submarines are normally not affected by wave action at all). Placing the majority of a ship's displacement
Displacement (ship)
A ship's displacement is its weight at any given time, generally expressed in metric tons or long tons. The term is often used to mean the ship's weight when it is loaded to its maximum capacity. A number of synonymous terms exist for this maximum weight, such as loaded displacement, full load...
under the waves is similar in concept to creating a ship that rides atop twin submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s.
Effects
The twin-hull design provides a stable platform and large, broad decks. The main disadvantages of SWATH watercraft are that they are more expensive than conventional catamaranCatamaran
A catamaran is a type of multihulled boat or ship consisting of two hulls, or vakas, joined by some structure, the most basic being a frame, formed of akas...
s or mono-hulls, require a complex control system, have a deeper draft
Draft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...
, and have higher maintenance requirements. The design of SWATH vessels is also considerably more complex due to the structural complexities inherent to the design. Additionally, SWATH vessels cannot operate in planing or semi-planing modes and as such gain no drag reduction when operating at speeds normally associated with such modes. This marginally limits SWATH speed when compared to equivalent catamaran vessels.
History
The SWATH form was invented by CanadianCanada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
Frederick G. Creed
Frederick G. Creed
Frederick George Creed was a Canadian inventor, who worked in the field of telecommunications, and played an early role in the development of SWATH vessels, The CCGS Frederick G...
, who presented his idea in 1938, and was later awarded a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
for it in 1946. It was first used in the 1960s and 1970s as an evolution of catamaran
Catamaran
A catamaran is a type of multihulled boat or ship consisting of two hulls, or vakas, joined by some structure, the most basic being a frame, formed of akas...
design for use in oceanographic
Oceanography
Oceanography , also called oceanology or marine science, is the branch of Earth science that studies the ocean...
research vessel
Research vessel
A research vessel is a ship designed and equipped to carry out research at sea. Research vessels carry out a number of roles. Some of these roles can be combined into a single vessel, others require a dedicated vessel...
s or submarine rescue ship
Submarine rescue ship
A Submarine rescue ship serves as a surface support ship for submarine rescue and deep-sea salvage operations. Methods employed are the McCann Rescue Chamber, Deep Submergence Rescue Vehicles and deep sea diving operations....
s.
Swath Ocean Systems Incorporated
Swath Ocean Systems Incorporated of San Diego, CaliforniaSan Diego, California
San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...
(later Swath Ocean Systems LLC) manufactured thses ships from 1979 to 2008 (the company folded sometime after this).
Specific examples
- CCGS Frederick G. CreedCCGS Frederick G. CreedThe CCGS Frederick G. Creed is a hydrographic survey vessel operated by the Canadian Coast Guard on behalf of the Canadian Hydrographic Service, a scientific agency of the Department of Fisheries and Oceans. The ship was built in 1988 by Swath Ocean Systems Incorporated of San Diego,...
, a Canadian Coast Guard survey ship - Sea Shadow, a US Navy experimental stealth ship
- Sea FighterSea FighterSea Fighter is an experimental littoral combat ship under development by the United States Navy. Its hull is of a small-waterplane-area twin-hull design, provides exceptional stability, even on rough seas. The ship can operate in both blue and littoral waters...
, a US Navy experimental littoral combat shipLittoral combat shipA Littoral Combat Ship is a type of relatively small surface vessel intended for operations in the littoral zone . It is "envisioned to be a networked, agile, stealthy surface combatant capable of defeating anti-access and asymmetric threats in the littorals." Two ship classes are the first... - Houbei class missile boatHoubei class missile boatThe Houbei class missile boat is a class in the People's Liberation Army Navy. The first boat was launched in April 2004 by the Qiuxin Shipbuilding Factory at Shanghai. The boats incorporate stealth features and wave-piercing catamaran hulls...
, a Chinese SWATH missile boat - MV Asia StarMV Asia StarMV Asia Star is a cruise ship run by Asia Cruises. It has a unique twin-hull/SWATH design and its gross tonnage is 20,050 tonnes. It is stationed in Hong Kong. It was formerly known as the Radisson Diamond, and built in Finland It has 12 decks and 170 guest rooms, displacing over 11,500 tons when...
(formerly the Radisson Diamond): a 350-person all balcony luxury cruise ship, the largest SWATH ship in the world when it was built, displacing more than 11,500 tons. - SunCruz VI, a USCG certificated casino vessel for 600 passengers
- RV Kilo MoanaRV Kilo Moana (T-AGOR-26)R/V Kilo Moana is a small waterplane area twin hull 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 fleet. She was designed to operate in coastal and blue water areas...
, a University of Hawaii oceanographic research vessel - Cloud X, a passenger ferry running between Florida and the Bahamas
- Nekton Pilot/Swacat 80, an 80-foot cruise ship operated by Nekton Diving Cruises
- Cetus and Perseus, pilot vessels for the Netherlands Loodswezen
- Döse, Dunen, pilot vessels for the German Brotherhood of Elbe - Pilots
- Elbe, pilot station vessel for the German Brotherhood of Elbe - Pilots
- PlanetPlanet class research shipThe Type 751 Planet of the German Navy is the most modern naval research ship within NATO. It was built as SWATH design in order to reduce the hull volume and to increase the ship's stability - particularly in high seas and at high speed....
Type 752, weapons + sonar research ship of the German NavyGerman NavyThe German Navy is the navy of Germany and is part of the unified Bundeswehr .The German Navy traces its roots back to the Imperial Fleet of the revolutionary era of 1848 – 52 and more directly to the Prussian Navy, which later evolved into the Northern German Federal Navy... - Western Flyerhttp://oceanexplorer.noaa.gov/technology/vessels/westernflyer/westernflyer.html a Monterey Bay Aquarium Research Institute (MBARI) research vessel
- The Goya, a fictional vessel in Dan BrownDan BrownDan Brown is an American author of thriller fiction, best known for the 2003 bestselling novel, The Da Vinci Code. Brown's novels, which are treasure hunts set in a 24-hour time period, feature the recurring themes of cryptography, keys, symbols, codes, and conspiracy theories...
's book Deception PointDeception PointDeception Point is a 2001 techno-thriller novel by Dan Brown. The plot concerns a meteorite found within the Arctic Circle that may provide proof of extraterrestrial life, and attempts by dark forces to prevent this finding from becoming public.-Plot:... - USNS Impeccable (T-AGOS-23), a U.S. Navy Impeccable-class ocean surveillance ship
See also
- MultihullMultihullA multihull is a ship, vessel, craft or boat with more than one hull.-Description:Multihulls include: Proas, which have two differently shaped or sized hulls with lateral symmetry; catamarans, which have two hulls with longitudinal symmetry; and trimarans, which have a main hull in the center and...
- M80 StilettoM80 StilettoThe M80 Stiletto is a prototype naval ship manufactured by the M Ship Company as an operational experiment for The Pentagon’s Office of Force Transformation. It is notable for its hull design and carbon fiber construction, as well as its networked architecture.-Design:The M80 Stiletto is a U.S....
- CatamaranCatamaranA catamaran is a type of multihulled boat or ship consisting of two hulls, or vakas, joined by some structure, the most basic being a frame, formed of akas...
- Sea SliceSea SliceHSV Sea Slice is an experimental United States Navy vessel, built by Lockheed Martin. Based on a variant of the SWATH hull design known as "SLICE", the Sea Slice is characterized by four teardrop-shaped submerged hulls, double the number seen on most previous designs...
, an experimental US Navy ship based upon the related technology called "SLICE". - Semisubmersible
- Hydroairy ship, another twin hull designhttp://www.mikrotehna.hr/hidrozracni_en.php
- TrimaranTrimaranA trimaran is a multihulled boat consisting of a main hull and two smaller outrigger hulls , attached to the main hull with lateral struts...
- wave-piercingWave-piercingA 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 stress on...