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.
A narrow waterline distinguishes a SWATH ship from a conventional catamaranA SWATH ship resembles a conventional catamaran. The twin hulls (blue) remain completely submerged.
The twin-hull design provides a stable platform and large, broad decks. Compared with conventional catamarans, SWATH vessels have more surface drag, but less wave drag. They are less susceptible to wave motion but more sensitive to payload, which affects draught. Additionally, SWATH vessels cannot operate in planing or semi-planing modes and thus gain no drag reduction when operating at speeds normally associated with such modes.[1] They require a complex control system, have a deeper draft, and have higher maintenance requirements. The design of SWATH vessels is also considerably more complex due to the structural complexities inherent to the design.[2]
HistoryEdit
The SWATH form was invented by CanadianFrederick G. Creed, who presented his idea in 1938, and was later awarded a British patent for it in 1946. The first full-scale SWATH vessel to be built and put into service was MV Duplus,[3] a diving support vessel built in the Netherlands in 1968. In the 1970s, several units were built in different countries (including the RV Kaimalino by the US Navy,[4] and an 80 ft (24 m) ferry in Japan). Since the 1980s, oceanographicresearch vessels, pilot tenders, yachts and other craft are more routinely being built with the SWATH hull type.[5]
^ Misra, Suresh Chandra (2015). Design Principles of Ships and Marine Structures. CRC Press. p. 474. ISBN9781482254471.
^Busch, Ian Richard (1990), On the Cost Effectivelness of Large Commercial SWATH Vessels, Cambridge: Massachusetts Institute of Technology, Department of Ocean Engineering, p. 418
^"Boele-Bolnes launch twin-hull craft for offshore work". Holland Shipbuilding. 17 (9): 58. 1968.
^LaPuzza, Tom (March 2005). "SSC San Diego Command History Calendar Year 2004" (PDF). United States Navy SSC SAN DIEGO. (PDF) from the original on February 28, 2017.
^ Arps, Jan L. (May 1973). "The Role of the Semi-Submersible Work Vessel In Offshore Production Operations". Fifth Annual Offshore Technology Conference. Offshore Technology Conference. doi:10.4043/1867-MS. ISBN978-1-55563-659-3.
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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 A narrow waterline distinguishes a SWATH ship from a conventional catamaranA SWATH ship resembles a conventional catamaran The twin hulls blue remain completely submerged Contents 1 Effects 2 History 3 Specific examples 4 See also 5 References 6 External linksEffects EditThe twin hull design provides a stable platform and large broad decks Compared with conventional catamarans SWATH vessels have more surface drag but less wave drag They are less susceptible to wave motion but more sensitive to payload which affects draught Additionally SWATH vessels cannot operate in planing or semi planing modes and thus gain no drag reduction when operating at speeds normally associated with such modes 1 They require a complex control system have a deeper draft and have higher maintenance requirements The design of SWATH vessels is also considerably more complex due to the structural complexities inherent to the design 2 History EditThe SWATH form was invented by Canadian Frederick G Creed who presented his idea in 1938 and was later awarded a British patent for it in 1946 The first full scale SWATH vessel to be built and put into service was MV Duplus 3 a diving support vessel built in the Netherlands in 1968 In the 1970s several units were built in different countries including the RV Kaimalino by the US Navy 4 and an 80 ft 24 m ferry in Japan Since the 1980s oceanographic research vessels pilot tenders yachts and other craft are more routinely being built with the SWATH hull type 5 Specific examples Edit nbsp German Navy research ship Planet nbsp German Federal Coast Guard customs cruiser HelgolandDuplus 1969 oil industry support ship the first SWATH ship built Sea Shadow 1984 US Navy experimental stealth ship CCGS Frederick G Creed 1988 Canadian Coast Guard survey ship USNS Victorious T AGOS 19 1988 lead ship of class of four US Navy surveillance ships that use a SURTASS Hibiki class ocean surveillance ships 6 1991 three patrol vessels operated by the Japan Maritime Self Defense Force MV China Star ex Radisson Diamond 1992 cruise ship largest SWATH when built displaces 20 000 t 20 000 long tons 22 000 short tons RV Western Flyer 1996 Monterey Bay Aquarium Research Institute mothership for the research ROV Doc Ricketts HSS 1500 1996 class of three Finnish high speed ferries withdrawn after a decade due to high fuel consumption USNS Impeccable T AGOS 23 2001 US Navy ocean surveillance ship that uses a SURTASS additional ships cancelled RV Kilo Moana T AGOR 26 2001 University of Hawaii oceanographic research vessel Planet 2005 German Navy weapons and sonar research ship Sea Fighter 2005 US Navy experimental littoral combat ship Silver Cloud 2008 41 m 135 ft private yacht NOAAS Ferdinand R Hassler 2009 a NOAA hydrographic survey vessel Type 639 oceanographic surveillance ship 2009 class of six vessels for the Chinese Navy M V Susitna 2010 ice capable convertible SWATH barge Ghost 2011 experimental super cavitating stealth ship Skrunda class patrol boat 2011 class of five 26 m 85 ft patrol vessels Iranian high aspect ratio twin hull vesselsSee also EditMultihull Ship or boat with more than one hull M80 Stiletto Prototype naval stealth vessel Catamaran Watercraft with two parallel hulls of equal size Sea Slice Experimental SWATH vessel an experimental US Navy ship with multiple SWATH hulls Semi submersible type of vessel which can partially submergePages displaying wikidata descriptions as a fallback Trimaran Multihull boat Wave piercing hull Hull with fine bow weth reduced reserve buoyancyReferences Edit Misra Suresh Chandra 2015 Design Principles of Ships and Marine Structures CRC Press p 474 ISBN 9781482254471 Busch Ian Richard 1990 On the Cost Effectivelness of Large Commercial SWATH Vessels Cambridge Massachusetts Institute of Technology Department of Ocean Engineering p 418 Boele Bolnes launch twin hull craft for offshore work Holland Shipbuilding 17 9 58 1968 LaPuzza Tom March 2005 SSC San Diego Command History Calendar Year 2004 PDF United States Navy SSC SAN DIEGO Archived PDF from the original on February 28 2017 Arps Jan L May 1973 The Role of the Semi Submersible Work Vessel In Offshore Production Operations Fifth Annual Offshore Technology Conference Offshore Technology Conference doi 10 4043 1867 MS ISBN 978 1 55563 659 3 AOS Hibiki Class GlobalSecurity org Archived from the original on September 5 2009 External links Edit nbsp Wikimedia Commons has media related to SWATH Retrieved from https en wikipedia org w index php title Small waterplane area twin hull amp oldid 1173005321, wikipedia, wiki, book, books, library,
