Small-waterplane-area twin hull

Last updated August 08, 2024

A SWATH ship resembles a conventional catamaran. The twin hulls (blue) remain completely submerged. Small waterplane area twin hull swath1 large.jpg — A SWATH ship resembles a conventional catamaran. The twin hulls (blue) remain completely submerged.

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.

Effects

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]

History

The 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

Duplus (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
RV Kaiyo [ jp ](1985):research vessel operated by the Japan Agency for Marine-Earth Science and Technology
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 vessels

Related Research Articles

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<span class="mw-page-title-main">Catamaran</span> Watercraft with two parallel hulls of equal size

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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 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.

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A moon pool is an equipment deployment and retrieval feature used by marine drilling platforms, drillships, diving support vessels, fishing vessels, marine research and underwater exploration or research vessels, and underwater habitats. It is also known as a wet porch. It is an opening found in the floor or base of the hull, platform, or chamber giving access to the water below. Because of its stable location, it safely allows technicians or researchers to lower tools and instruments into the sea.

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The Impeccable-class ocean surveillance ship is a single-ship class of United States Navy special mission-support ship. The original intention was to build six undersea ocean-surveillance ships carrying a SURTASS passive towed array and a Low Frequency Active transducer array. Only the lead ship, USNS Impeccable (T-AGOS-23), was built.

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.

JS Hibiki (AOS-5201) is a Hibiki-class ocean surveillance ship of Japan Maritime Self-Defense Force.

RV Moana Wave (AGOR-22),, is the second ship of the Gyre-class oceanographic research ship built in 1973.

References

↑ 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

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[1] Misra, Suresh Chandra (2015). Design Principles of Ships and Marine Structures. CRC Press. p. 474. ISBN 9781482254471.

[2] Busch, Ian Richard (1990), On the Cost Effectivelness of Large Commercial SWATH Vessels, Cambridge: Massachusetts Institute of Technology, Department of Ocean Engineering, p. 418

[3] "Boele-Bolnes launch twin-hull craft for offshore work". Holland Shipbuilding. 17 (9): 58. 1968.

[4] 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.

[5] 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.

[GlobalSecuritySpecifications-6] "AOS Hibiki Class". GlobalSecurity.org. Archived from the original on September 5, 2009.

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