What Is a Characteristic of a Catamaran Hull?

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Additionally, because of the hull design, catamarans boast a smaller hydrodynamic resistance, ultimately making them more economic since they don’t need as much fuel to propel them forward. And for those sailors still strengthening their sea legs, the double hull increases the catamaran‘s overall balance and stability by reducing the amount of wave-induced motion.

have two hulls, usually connected by a bridgedeck can be sailed in shallow water use less fuel, because they have low hydrodynamic resistance tend to be very stable have a lot of space for dining and lounging and preparing food offer greater privacy than monohull yachts

What is a characteristic of a catamaran hull quizlet?

What is a characteristic of a catamaran hull? A Stable Ride. What is true of a No Discharge Zone or NDZ? Discharge of sewage is illegal.

What is a characteristic of a catamaran hull planes at low speed?

What is a characteristic of a catamaran hull planes at low speed? Planes at low speed. Tends to pitch in waves. A stable ride.

What is catamaran hull?

A catamaran is a boat that has two hulls instead of a single hull which the traditionally designed one-hulled boats have. Catamarans were designed to be fishing boats though their use has increased and widened manifold in today’s times.

Does a catamaran hull pitch in waves?

When a catamaran encounters a wave at the bows it will first immerse the bows more deeply which starts them rising upward due to the increased buoyancy of the immersed hull. As result the boat will rotate (pitch) positively. … The boat must be able to pitch upward in order to sail over waves.

A catamaran (/ktmrn/) (informally, a “cat”) 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.

Catamarans range in size from small sailing or rowing vessels to large naval ships and roll-on/roll-off car ferries. The structure connecting a catamaran‘s two hulls ranges from a simple frame strung with webbing to support the crew to a bridging superstructure incorporating extensive cabin and/or cargo space.

However, the original kattumaram did not refer to double-hulled boats at all, but to a type of single-hulled raft made of three to seven tree trunks lashed together. Two canoes bound together developed directly from minimal raft technologies of two logs tied together. This would also explain why older Austronesian populations in Island Southeast Asia tend to favor double outrigger canoes, as it keeps the boats stable when tacking .

Crisp described it as “a fast sailing fine sea boat; she traded during the monsoon between Rangoon and the Tenasserim Provinces for several years”. Later that century, the American Nathanael Herreshoff constructed a double-hulled sailing boat of his own design (US Pat. Her debut demonstrated the distinct performance advantages afforded to catamarans over the standard monohulls.

It was as a result of this event, the Centennial Regatta of the New York Yacht Club, that catamarans were barred from regular sailing classes, and this remained the case until the 1970s. [23] The claimed advantage of this sail plan was to diminish any tendency for the bows of the vessel to dig in. Hobie 16 beachable catamaranIn the mid-twentieth century, beachcats became a widespread category of sailing catamarans, owing to their ease of launching and mass production.

[[HSC Francisco ]]; the world’s fastest passenger ship Catamarans have two distinct primary performance characteristics that distinguish them from displacement monohull vessels: lower resistance to passage through the water and greater stability (initial resistance to capsize). Choosing between a monohull and catamaran configuration includes considerations of carrying capacity, speed, and efficiency. Vangohh Seafarer , a catamaran motor yacht berthed at Straits Quay, Georgetown, Pulau Pinang, MalaysiaOne measure of the trade-off between speed and carrying capacity is the displacement Froude number (Fn V ) , [40] compared with calm water transportation efficiency .

[42] It uses a reference length, the cubic root of the volumetric displacement of the hull, V , where u is the relative flow velocity between the sea and ship, and g is acceleration due to gravity : FnV=ugV1/3{\displaystyle \mathrm {Fn_{V}} ={\frac {u}{\sqrt {gV^{1/3}}}}} Calm water transportation efficiency of a vessel is proportional to the full-load displacement and the maximum calm-water speed, divided by the corresponding power required. It was first used in the 1960s and 1970s as an evolution of catamaran design for use as oceanographic research vessels or submarine rescue ships.

Larger wetted surface, which causes higher skin friction drag Significant reduction in wave-induced drag, with the configuration of struts and submerged hull structures Lower water plane area significantly reduces pitching and heaving in a seaway No possibility of planing Higher sensitivity to loading, which may bring the bridge structure closer to the water The spanning bridge deck may be configured with some of the characteristics of a normal V-hull, which allows it to penetrate the crests of waves. Emirates Team New Zealand’s AC72 Aotearoa on foils in San Francisco BayTechnological advances catamerans have over traditional monohull craft include foils that lift racing catamarans out of the water, capacious and stable cruising vessels, and racers that have achieved average speeds on the open ocean, comparable to much larger vessels.

Recreational and sport catamarans typically are designed to have a crew of two and be launched and landed from a beach. Performance versions often have trapezes to allow the crew to hike out and counterbalance capsize forces during strong winds on certain points of sail. This represented a break from the traditional monohulls that had always been sailed in previous America’s Cup series.

The Race ” helped precipitate this trend; it was a circumnavigation challenge which departed from Barcelona, Spain, on New Year’s Eve, 2000. Because of the prize money and prestige associated with this event, four new catamarans (and two highly modified ones) over 100 feet (30 m) in length were built to compete. The frame of the tourist catamaran can be made of both aluminum (duralumin) pipes and from felled tree trunks.

[57] A cata-raft design has been used on the Colorado River to handle heavy whitewater, yet maintain a good speed through the water. Cruising sailors must make trade-offs among volume, useful load, speed, and cost in choosing a boat. Choosing a catamaran offers increased speed at the expense of reduced load per unit of cost.

In addition to greater speed, catamarans draw less water than do monohullslittle as 3 feet (0.91 m)and are easier to beach. Tarjan adds that cruising catamarans boats can maintain a comfortable 300 nautical miles (350 mi; 560 km) per day passage, with the racing versions recording well over 400 nautical miles (460 mi; 740 km) per day. ^ The Origins and Ethnological Significance
Of Indian Boat Designs JAMES HORNELL
Director of Fisheries, Madras Government
The Origins and Ethnological Significance
Of Indian Boat Designs
Memoirs of the Asiatic Society of Bengal
Calcutta 1920 ^ a b c Mahdi, Waruno (1999).

A treatise on marine architecture, elucidating the theory of the resistance of water : illustrating the form, or model best calculated to unite velocity, buoyancy, stability, strength, etc., in the same vessel : and finally, adducing the theory of the art of shipbuilding . ^ Sampsell, Lorillard D. (March 1898), “The Southern Yacht Club of New Orleans” , Outing: Sport, Adventure, Travel Fiction, Volume 31 ^ Counce, Oliver J. (2000), “The sesquicentennial of the Southern Yacht Club of New Orleans, 1849-1999 : 150 years of yachting in the Gulf South”, Metairie Franklin Southland Printing , OCLC 46836336 ^ The Voyage of the Kaimiloa , London, 1940 (translated from French: Kaimiloa : D’Honolulu Cannes par l’Australie et Le Cap, bord d’une double pirogue polynsienne ), Editions Plon, Paris, 1939 ( Au del des horizons lointains 1 ).

CS1 maint: numeric names: authors list ( link ) ^ “Hobie 16 2012 Class Report 2012” (PDF) . ^ “Oracle Team USA completes greatest comeback in America’s Cup history, defeating Emirates New Zealand” .

Catamaran

ACatamarans were invented by the Austronesian peoples which enabled their expansion to the islands of the Indian and Pacific Oceans.Catamarans range in size from small sailing or rowing vessels to large naval ships and roll-on/roll-off car ferries. The structure connecting a catamaran‘s two hulls ranges from a simple frame strung with webbing to support the crew to a bridging superstructure incorporating extensive cabin and/or cargo space.

History[edit]

Catamarans from Oceania and Maritime Southeast Asia became the inspiration for modern catamarans. Until the 20th century catamaran development focused primarily on sail-driven concepts.

Etymology[edit]

The word “catamaranis derived from the Tamil word,

Development in Oceania and Asia[edit]

Catamaran-type vessels were an early technology of the Austronesian peoples. Early researchers like Heine-Geldern (1932) and Hornell (1943) once believed that catamarans evolved from outrigger canoes, but modern authors specializing in Austronesian cultures like Doran (1981) and Mahdi (1988) now believe it to be the opposite.Two canoes bound together developed directly from minimal raft technologies of two logs tied together. Over time, the double-hulled canoe form developed into the asymmetric double canoe, where one hull is smaller than the other. Eventually the smaller hull became the prototype outrigger, giving way to the single outrigger canoe, then to the reversible single outrigger canoe. Finally, the single outrigger types developed into the double outrigger canoe (or trimarans).This would also explain why older Austronesian populations in Island Southeast Asia tend to favor double outrigger canoes, as it keeps the boats stable when tacking. But they still have small regions where catamarans and single-outrigger canoes are still used. In contrast, more distant outlying descendant populations in Oceania, Madagascar, and the Comoros, retained the double-hull and the single outrigger canoe types, but the technology for double outriggers never reached them (although it exists in western Melanesia). To deal with the problem of the instability of the boat when the outrigger faces leeward when tacking, they instead developed the shunting technique in sailing, in conjunction with reversible single-outriggers.Despite their being the more “primitive form” of outrigger canoes, they were nonetheless effective, allowing seafaring Polynesians to voyage to distant Pacific islands.

Traditional catamarans[edit]

The following is a list of traditional Austronesian catamarans:

Western development[edit]

The first documented example of double-hulled sailing craft in Europe was designed by William Petty in 1662 to sail faster, in shallower waters, in lighter wind, and with fewer crew than other vessels of the time. However, the unusual design met with skepticism and was not a commercial success.The design remained relatively unused in the West for almost 160 years until the early 19th-century, when the Englishman Mayflower F. Crisp built a two-hulled merchant ship in Rangoon, Burma. The ship was christenedLater that century, the American Nathanael Herreshoff constructed a double-hulled sailing boat of his own design (US Pat. No. 189,459).In 1936, Eric de Bisschop built a Polynesian “double canoe” in Hawaii and sailed it home to a hero’s welcome in France. In 1939, he published his experiences in a book,Roland and Francis Prout experimented with catamarans in 1949 and converted their 1935 boat factory in Canvey Island, Essex (England), to catamaran production in 1954. TheirIn the mid-twentieth century, beachcats became a widespread category of sailing catamarans, owing to their ease of launching and mass production. In California, a maker of surfboards, Hobie Alter, produced the 250-pound (110 kg) Hobie 14 in 1967, and two years later the larger and even more successful Hobie 16. As of 2016, the Hobie 16 was still being produced with more than 100,000 having been manufactured.Catamarans were introduced to Olympic sailing in 1976. The two-handed Tornado catamaran was selected for the multihull discipline in the Olympic Games from 1976 through 2008. It was redesigned in 2000.The Australian island Tasmania became the site of builders of large transport catamarans—Incat in 1977

Performance[edit]

Catamarans have two distinct primary performance characteristics that distinguish them from displacement monohull vessels: lower resistance to passage through the water and greater stability (initial resistance to capsize). Choosing between a monohull and catamaran configuration includes considerations of carrying capacity, speed, and efficiency.

Resistance[edit]

At low to moderate speeds, a lightweight catamaran hull experiences resistance to passage through water that is approximately proportional to the square of its speed. A displacement monohull, by comparison, experiences resistance that is at least the cube of its speed. This means that a catamaran would require four times the power in order to double its speed, whereas a monohull would require eight times the power to double its speed, starting at a slow speed.

Stability[edit]

Catamarans rely primarily on form stability to resist heeling and capsize.

Tradeoffs[edit]

One measure of the trade-off between speed and carrying capacity is the displacement Froude number (FnLarge merchant vessels have a Fn

Applications[edit]

Two advances over the traditional catamaran are theSWATH reduces wave-generating resistance by moving displacement volume below the waterline, using a pair of tubular, submarine-like hulls, connected by pylons to the bridge deck with a narrow waterline cross-section. The submerged hulls are minimally affected by waves.SWATH vessels compare with conventional powered catamarans of equivalent size, as follows:Wave-piercing catamarans employ a low-buoyancy bow on each hull that is pointed at the water line and rises aft, up to a level, to allow each hull to pierce waves, rather than ride over them. This allows higher speeds through waves than for a conventional catamaran. They are distinguished from SWATH catamarans, in that the buoyant part of the hull is not tubular. The spanning bridge deck may be configured with some of the characteristics of a normal V-hull, which allows it to penetrate the crests of waves.Wave-piercing catamaran designs have been employed for yachts,

Sport[edit]

Recreational and sport catamarans typically are designed to have a crew of two and be launched and landed from a beach. Most have a trampoline on the bridging structure, a rotating mast and full-length battens on the mainsail. Performance versions often have trapezes to allow the crew to hike out and counterbalance capsize forces during strong winds on certain points of sail.For the 33rd America’s Cup, both the defender and the challenger built 90-foot (27 m) long multihulls. Société Nautique de Genève, defending with team Alinghi, sailed a catamaran. The challenger, BMW Oracle Racing, used a trimaran, replacing its soft sail rig with a towering wing sail—the largest sailing wing ever built. In the waters off Valencia, Spain in February 2010, the BMW Oracle Racing trimaran with its powerful wing sail proved to be superior. This represented a break from the traditional monohulls that had always been sailed in previous America’s Cup series.On San Francisco Bay, the 2013 America’s Cup was sailed in 72-foot (22 m) long AC72 catamarans (craft set by the rules for the 2013 America’s Cup). Each yacht employed hydrofoils and a wing sail. The regatta was won 9-8 by Oracle Team USA against the challenger, Emirates Team New Zealand, in fifteen matches because Oracle Team USA had started the regatta with a two-point penalty.Yachting has seen the development of multihulls over 100 feet (30 m) in length. “The Race” helped precipitate this trend; it was a circumnavigation challenge which departed from Barcelona, Spain, on New Year’s Eve, 2000. Because of the prize money and prestige associated with this event, four new catamarans (and two highly modified ones) over 100 feet (30 m) in length were built to compete. The largest,Whitewater catamaran—sometimes called “cata-rafts”—for whitewater sports are widely spread in post-Soviet countries. They consists of two inflatable hulls connected with a lattice scaffold. The frame of the tourist catamaran can be made of both aluminum (duralumin) pipes and from felled tree trunks. The inflatable part has two layers—an airtight balloon with inflation holes and a shell made of dense tissue, protecting the balloon from mechanical damage. Advantages of such catamarans are light weight, compactness and convenience in transportation (the whole product is packed in one pack-backpack, suitable for air traffic standards) and the speed of assembly (10–15 minutes for the inflation).

Cruising[edit]

Cruising sailors must make trade-offs among volume, useful load, speed, and cost in choosing a boat. Choosing a catamaran offers increased speed at the expense of reduced load per unit of cost. Howard and Doane describe the following tradeoffs between cruising monohulls and catamarans:Powered cruising catamarans share many of the amenities found in a sail cruising catamaran. The saloon typically spans two hulls wherein are found the staterooms and engine compartments. As with sailing catamarans, this configuration minimizes boat motion in a seaway.The Swiss-registered wave-piercing catamaran,

Passenger transport[edit]

The 1970s saw the introduction of catamarans as high-speed ferries, as pioneered by Westermoen Hydrofoil in Mandal, Norway, which launched the Westamaran design in 1973.

Military[edit]

The first warship to be propelled by a steam engine, namedIn the early 20th Century several catamarans were built as submarine salvage ships: SMSThe use of catamarans as high-speed naval transport was pioneered by HMASTheFirst launched in 2004 at Shanghai, the Houbei class missile boat of the People’s Liberation Army Navy (PLAN) has a catamaran design to accommodate the vessel’s stealth features.