Catamaran

The word "catamaran" is derived from the Tamil word, kattumaram (கட்டுமரம்), which means "logs bound together". However, the original kattumaram did not refer to double-hulled boats at all, but to a type of single-hulled raft of the Tamil people made of three to seven tree trunks lashed together. The term has evolved in English usage to refer solely to unrelated double-hulled boats.[2][3][4][5] [6][7]

Succession of forms in the development of the Austronesian boat (Mahdi, 1999)

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.[8][9][1]

Hōkūleʻa, a modern replica of a Polynesian double-hulled voyaging canoe—an Austronesian innovation

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).[8][9][1]

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.[8][9][1][10][11]

Despite their being the more "primitive form" of outrigger canoes, they were nonetheless effective, allowing seafaring Polynesians to voyage to distant Pacific islands.[12]

Model of a Fijian drua with a crab-claw sail from the Otago Museum

The following is a list of traditional Austronesian catamarans:

• Island Melanesia:

• Fiji: Drua (or Wangga tabu)
• Papua New Guinea: Lakatoi
• Tonga: Hamatafua, Kalia, Tongiaki

• Polynesia

• Cook Islands: Vaka katea
• Hawaii: Waʻa kaulua
• Marquesas: Vaka touʻua
• New Zealand: Waka hourua
• Samoa: ʻAlia, Amatasi, Va'a-tele
• Society Islands: Pahi, Tipairua

Nathaniel Herreshoff's 31 ft (9 m) long catamaran, Duplex, on the River Thames—built in 1877

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.[13][14]

Vangohh Seafarer, a catamaran motor yacht berthed at Straits Quay, Georgetown, Pulau Pinang, Malaysia

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 christened Original. Crisp described it as "a fast sailing fine sea boat; she traded during the monsoon between Rangoon and the Tenasserim Provinces for several years".[15][16]

Later that century, the American Nathanael Herreshoff constructed a double-hulled sailing boat of his own design (US Pat. No. 189,459).[17] The craft, Amaryllis, raced at her maiden regatta on June 22, 1876, and performed exceedingly well. 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.[18] On June 6, 1882, three catamarans from the Southern Yacht Club of New Orleans raced a 15nm course on Lake Pontchartrain and the winning boat in the catamaran class, Nip and Tuck, beat the fastest sloop's time by over five minutes.[19][20]

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, Kaimiloa, which was translated into English in 1940.[21]

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. Their Shearwater catamarans easily won races against monohulls. Yellow Bird, a 1956-built Shearwater III, raced successfully by Francis Prout in the 1960s, is in the collection of the National Maritime Museum Cornwall.[22] Prout Catamarans, Ltd. designed a mast aft rig with the mast aft of midships to support an enlarged jib—more than twice the size of the design's reduced mainsail; it was produced as the Snowgoose model.[23] The claimed advantage of this sail plan was to diminish any tendency for the bows of the vessel to dig in.[24][25]

Hobie 16 beachable catamaran

In 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.[26]

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.[27] The foiling Nacra 17 will be used in the Tokyo 2020 Olympics,[28][29] after the 2015 adoption of the Nacra 15 as a Youth World Championships class and as a new class for the Youth Olympic Games.[30][31]

Australia became the site of builders of large transport catamarans—Incat in 1977[32] and Austal in 1988[33]—each building civilian ferries and naval vessels.

The largest ship ever built in terms of gross tonnage, the Pioneering Spirit, incorporates a catamaran design.[34]

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.[35] For powered catamarans, this implies smaller power plants (although two are typically required). For sailing catamarans, low forward resistance[36] allows the sails to derive power from attached flow,[37] their most efficient mode—analogous to a wing—leading to the use of wingsails in racing craft.[38]

Catamarans rely primarily on form stability to resist heeling and capsize.[35] Comparison of heeling stability of a rectangular-cross section monohull of beam, B, compared with two catamaran hulls of width B/2, separated by a distance, 2×B, determines that the catamaran has an initial resistance to heeling that is seven times that of the monohull.[39] Compared with a monohull, a cruising catamaran sailboat has a high initial resistance to heeling and capsize—a fifty-footer requires four times the force to initiate a capsize than an equivalent monohull.[40]

One measure of the trade-off between speed and carrying capacity is the displacement Froude number (Fn_V),[41] compared with calm water transportation efficiency.[42] Fn_V applies when the waterline length is too speed-dependent to be meaningful—as with a planing hull.[43] 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:

${\displaystyle \mathrm {Fn_{V}} ={\frac {u}{\sqrt {gV^{1/3}}}}}$

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.[44]

Large merchant vessels have a Fn_V between one and zero, whereas higher-performance powered catamarans may approach 2.5—denoting a higher speed per unit volume for catamarans. Each type of vessel has a corresponding calm water transportation efficiency, with large transport ships being in the range of 100–1,000, compared with 11-18 for transport catamarans—denoting a higher efficiency per unit of payload for monohulls.[42]

Gitana 13, an ocean-racing catamaran

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.[52]

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.[53]

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.[54][55]

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, PlayStation, owned by Steve Fossett, was 125 feet (38 m) long and had a mast which was 147 feet (45 m) above the water. Virtually all of the new mega-cats were built of pre-preg carbon fiber for strength and the lowest possible weight. The top speeds of these boats can approach 50 knots (58 mph; 93 km/h). The Race was won by the 33.50 m (109.9 ft)-long catamaran Club Med skippered by Grant Dalton. It went round the globe in 62 days at an average speed of 18 knots (21 mph; 33 km/h).[56]

Catamarans for whitewater sports. Picture was taken in Altai, Russia

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).[57] All-inflatable models are available in North America.[58] A cata-raft design has been used on the Colorado River to handle heavy whitewater, yet maintain a good speed through the water.[59]

A cruising catamaran

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:[40] A long-distance, offshore cruising monohull may be as short as 30 feet (9.1 m) for a given crew complement and supporting supplies, whereas a cruising catamaran would need to be 40 feet (12 m) to achieve the same capacity. In addition to greater speed, catamarans draw less water than do monohulls—little as 3 feet (0.91 m)—and are easier to beach. Catamarans are harder to tack and take up more space in a marina. Cruising catamarans entail added expense for having two engines and two rudders. 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. In addition, they do not heel more than 10-12 degrees, even at full speed on a reach.[60]

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.[61]

The Swiss-registered wave-piercing catamaran, Tûranor PlanetSolar, which was launched in March 2010, is the world's largest solar powered boat. It completed a circumnavigation of the globe in 2012.[62]

The HSC Stena Voyager a catamaran passenger ferry

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.[63] The Stena Voyager was an example of a large, fast ferry, typically traveling at a speed of 46 miles per hour (74 km/h), although it was capable of over 70 miles per hour (110 km/h).[64]

US Naval Ship Spearhead (JHSV-1) during sea trials in 2012

Military Sealift Command operates several Expeditionary Fast Transport catamarans owned by the U.S. Navy.[65] They are used for high speed transport of military cargo, and to get into shallow ports.

The Makar-class is a class of two large catamaran-hull survey ships built for the Indian Navy. As of 2012, one vessel, INS Makar (J31), was in service and the second was under construction.[66]

First 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.[67]