Hydrofoil

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This article is about marine engineering. For the topic in fluid dynamics, see Airfoil.

The Jetfoil Toppi is a ferry which connects Yakushima, Tanegashima Island and Kagoshima port in Japan.

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A hydrofoil is a boat with wing-like foils mounted on struts below the hull. As the craft increases its speed the hydrofoils develop enough lift for the boat to become foilborne - i.e. to raise the hull up and out of the water. This results in a great reduction in drag and a corresponding increase in speed.

Early hydrofoils used U-shape foils. Hydrofoils of this type are known as surface-piercing since portions of the U-shape hydrofoils will rise above the water surface when foilborne. Modern hydrofoils use T-shape foils which are fully submerged. Fully submerged hydrofoils are less subjected to the effects of wave action, and are therefore more stable at sea and are more comfortable for the crew and passengers. This type of configuration, however, is not self-stabilizing. The angle of attack on the hydrofoils needs to be adjusted continuously in accordance to the changing conditions, a control process that is performed by computers. Failure to make the proper adjustments will result in the foilborne hull dropping violently back into the sea.

The term "hydrofoil" is also used to refer to the foil itself, especially when the airfoil profile has been specifically designed for use in water (such as for a propeller blade).

1 History
2 Current operation
3 Gallery
4 See also
5 External links

[edit] History

Forlanini hydrofoil over Lake Maggiore, 1910.

A March 1906 Scientific American article by American hydrofoil pioneer William E. Meacham explained the basic principle of hydrofoils. Alexander Graham Bell considered the invention of the hydroplane a very significant achievement. After reading this article Bell began to sketch concepts of what is now called a hydrofoil boat. With Casey Baldwin, he began hydrofoil experimentation in the summer of 1908. Baldwin studied the work of the Italian inventor Enrico Forlanini and began testing models based on his designs. This led him and Bell to the development of hydrofoil watercraft. During Bell's world tour of 1910-1911 he and Baldwin met with Forlanini in Italy. They had rides in the Forlanini hydrofoil boat over Lake Maggiore. Baldwin described it as being as smooth as flying. On returning to Baddeck a number of designs were tried culminating in the HD-4. Using Renault engines a top speed of 87 km/h (54 mph) was achieved, accelerating rapidly, taking wave without difficulty, steering well and showing good stability. Bell's report to the United States Navy permitted him to obtain two 260 kW (350 horsepower) engines. On September 9, 1919 the HD-4 set a world marine speed record of 114 km/h (70.86 mph). This record stood for ten years.

Between 1873 and 1914, the British boat designer John I Thornycroft worked on a series of models with a stepped hull and single bow foil. In 1909 his company built a full scale 22 foot long boat, Miranda III, driven by 60 hp engine that rode on a bowfoil and flat stern. The subsequent Miranda IV was credited with 35 knots. [1].

Baron von Schertel worked on hydrofoils prior to and during World War II in Germany. After the war Schertel's team was captured by the Russians. Schertel himself went to Switzerland, where he established the Supramar company. In 1952, Supramar launched the first commercial hydrofoil, PT10, in Lake Maggiore, between Switzerland and Italy. The PT10 is of surface-piercing type, it can carry 32 passengers and travel at 35 knots. In 1968, the financier Hussain Najadi acquired the Supramar AG and expanded its operations into Japan, Hong Kong, Singapore, UK, Norway and USA. General Dynamics of the United States became its licensee, and the Pentagon awarded its first R&D naval research project in the field of super cavitations. Hitachi Shipbuilding of Osaka, Japan, was another licensee of Supramar, as well as many leading ship owners and shipyards in the OECD countries.

From 1952 to 1971, Supramar designed many models of hydrofoils: PT20, PT50, PT75, PT100 and PT150. Except the PT150, all are of surface-piercing type. Over 200 of Supramar's design were built, most of them by Rodriquez in Italy.

The Canadian Navy built and tested a high-speed anti-submarine hydrofoil, the HMCS Bras d'Or, in the late 1960s, but the program was cancelled due to a shift away from ASW by the Canadian Navy. The Bras d'Or was a surface-piercing type which performed well during her trials, reaching a maximum speed of 63 knots.

The Soviet Union experimented extensively with hydrofoils, constructing hydrofoil river boats and ferries with streamlined designs, especially during the 1970s and 1980s. Such vessels include the Raketa (1957) type, followed by the larger Meteor type and the smaller Voskhod type.

The U.S. Navy operated combat hydrofoils, such as the Pegasus class, from 1977 through 1993. These hydrofoils were fast and well armed, and were capable of sinking all but the largest surface vessels. In their narcotics interdiction role, they were a nightmare for drug runners, being very fast, and having missiles and guns to stop anything they could not catch, as well as the ability to call in air support.

The Italian Navy has used 6 hydrofoils of the Nibbio class from the late 1970s. These were armed with a 76 mm gun, two missiles and were capable of speed up to 50 knots.

The French experimental sail powered hydrofoil Hydroptère is the result of a research project that involves advanced engineering skills and technologies. In January 2007, the Hydroptère has reached speeds in excess of 45 knots.

[edit] Current operation

Some operators of hydrofoil include:

TurboJET service, which speeds passengers across the Pearl River Delta between Hong Kong and Macau in less than an hour, with an average speed of 45 knots (83km/h), mainly using Boeing's Jetfoil. Also services Shenzhen, Guangzhou and Kowloon. Operated by Shun Tak-China Travel Ship Management Limited.
Meteor service between St. Petersburg, Russia and the Peterhof, a summer palace of Russian tsars.
Meteor service between St. Petersburg, Russia and the Kronstadt, a strongly fortified Russian seaport town, located on Kotlin Island, near the head of the Gulf of Finland. It lies thirty kilometers west of Saint Petersburg.
Meteor, Raketa and Voskhod hydrofoil types operate all over Volga, Don and Kama Rivers in Russia.
Meteor hydrofoils are operated by a number of tour operators in Croatia, mostly for packaged tours, but there are also some scheduled services to islands in Adriatic.
Linda Line between Tallinn and Helsinki, using two Morye's Olympias, Ukrainian built and Mercedes-Benz powered hydrofoils.
Hydrofoils are regularly operated on the three major Italian Lakes by branches of Ministry Of Transportation: Navigazione Lago Maggiore services routes on the Lake Maggiore between Locarno and Arona, Navigazione Lago di Como services routes on the Lake Como and Navigazione Lago di Garda services routes on the Lake Garda. Three units of the Rodriquez RHS150 type operate on each lake, for a total of nine hydrofoils. Navigazione Lago di Como still operates the last Rodriquez RHS70 in active service in Italy.
Former Russian hydrofoils are used in southern Italy for connection with islands of Lazio and Campania.
Beetle service between Pusan, South Korea and Fukuoka, Japan, it services five times a day, mainly using Boeing's Jetfoil.
Regular hydrofoil service from Istanbul to Yalova.
Fast Flying Ferries operated by Connexxion, provides a regular public transport service over the North Sea Canal between Amsterdam Central Station and Velsen-Zuid in The Netherlands, using Voskhod 2M hydrofoils.
Flying Dolfins operate in many lines in the Aegean, between the Cycladic islands and Athens.
Meteor (2), Polesye (4) and Voskhod (3) hydrofoil types operate in Hungary. MAHART PassNave Ltd. operates scheduled hydrofoil liners between Budapest, Bratislava and Vienna, inland liners between Budapest and the Danube Bend, and theme cruises to Komárom, Solt, Kalocsa and Mohács.
Russian hydrofoils of the Kometa type operated on the Bulgarian Black Sea Coast connecting Varna, Nesebar, Burgas, Sozopol, Primorsko, and Tsarevo, and Raketa and Meteor models served the Bulgarian Danube ports between Rousse and Vidin. Both services were discontinued in the 1990s but may be reopened.
Vietnamese Greenline Company operates hourly shuttle service between Ho Chi Minh city, Vung Tau and Con Dao island. Hydrofoil lines using the Russian-built Meteor type also connect Hai Phong, Ha Long and Mong Cai in North Vietnam, Phan Thiet and Phu Quy island and between Rach Gia and Phu Quoc island in the South.

[edit] Gallery

The USS Plainview (AGEH–1) was, in its time, the world’s largest hydrofoil; she was also the United States Navy’s first hydrofoil research ship.	In Russia, a Meteor floats in displacement mode near Peterhof preparing to travel through the Gulf of Finland to the Winter Palace in St. Petersburg.	WSS-12 from Friedrich H. Wendel	USS Aquila, a military hydrofoil. The T-shaped foils are visible just below the water.
Raketa on the Volga river (2004).	A Meteor in China on the Yangtze River, running downstream fast on its hydrofoils.	A Volgan Meteor is prepared to pass a winter in Kazan, Tatarstan, Russia. In countries where rivers are covered with ice during the winter, hydrofoils are often extracted from water, as ice can damage the foils.