• 2021 November 10

    Flying ships: prospects of hovercraft

    Hovercraft А48 with passengers. Image source: Wikipedia

    Following our earlier insight into the prospects of hydrofoils we will now focus on hovercraft, another promising segment in domestic and global shipbuilding.

    Some experts used to claim that the era of hydrofoils is over with their operation being inefficient due to frequent damage of foils. Meanwhile, hovercraft have never been a widespread type of passenger transport. The reason behind it is a higher cost of operation as compared with other ships including ships of displacement-type, hydrofois and planing ships. Actually, power is needed no only to move a ship but also to create an air cushion with the latter accounting for one third of the engine capacity. So, hovercraft in the segment of high-speed fleet are comparable to helicopters in the segment of air transport. The function of a helicopter’s lifting rotor is both maintaining an aircraft in air and directing it. However, helicopters are less dependent on infrastructure so they can perform tasks that cannot be performed by airplanes. The same can be said about hovercraft. One of their prime advantages is the ability move in shallow waters and on waterways that are considered to be non-navigable. A hovercraft can move straight-forwardly to avoid following the turns of waterways or move above ice-covered waters which helps address seasonal problems of water transport. A disadvantage of hovercraft, apart from their high operation costs, is their dependence on wind which affects the speed. Besides, they are difficult to steer with aerodynamic steering techniques being effective only at quite high speed.

    From a commercial point of view, a crucial advantage of hovercraft is the ability of year-round operation. In Russia, ships of this type have a considerable market potential as vast territories of the country have a cold climate and long severe winters. Economically, no need for berths is another advantage of such vessels.

    An attempt to introduce hovercraft into the passenger segment was undertaken last century. A ship for 50 passengers named Sormovich was built in 1965. Its power plant included a gas turbine engine АИ-20К and an auxiliary engine АИ-8, both designed by A.Ivchenko. The vessel’s speed was 110-130 km/h. It operated on the Gorky-Cheboksary line.

    More attempts to organize passenger transportation by hovercraft were also undertaken in post-reform Russia. The first line, an international one, launched in 1992 linked Blagoveshchensk and Heihe of China. The second line opened in 2002 between Samara and Rozhdestveno. The third one crossed the Volga river from Nizhny Novgorod to Bor.  Between 2008 and 2014, those lines were operated by a private company, Logoprom-Borsky Perevoz. It also arranged 4 routes including 3 in Nizhny Novgorod and 1 in the Moscow Region. All of them were soon closed due to low demand.

    Image source: Wikipedia

    Hovercraft can also be used in the cargo segment. They can be useful for transit cargo transportation between the North Atlantic areas and the northern part of the Pacific Ocean. The length of trade lines could be reduced considerably with them. Sea leg of 9 lines including London-Tokyo and London Anchorage can be reduced by 40%. With a high speed of hovercraft, transit cargo delivery time can be cut 10 times as compared with ships of displacement-type. Hovercraft can transport passengers and cargoes across the glacier sheet between the Arctic areas and the northern shore as well as between the southern ports. However, the key role can be played in development of mineral resources and in local transportation of food, construction materials and equipment.

    In other countries, hovercraft have been in operation from 1959. Most of them were built in Great Britain but their manufacture was also established in Japan, the USA, France and the USSR. Such ships have carried millions of passengers by regular lines across the English Channel and the Irish Sea, along the Mediterranean coast of France and Italy, in Canada, in the USA and in the Caribbean countries as well as in Japan and Australia. Most of hovercraft can accommodate up to 100 passengers but ships of 5К4 design put into operation from 1968 can accommodate 254 passengers and 30 passenger cars. It takes them 40 minutes to cross the English Channel. In 1976, about 2 million passengers crossed the Channel by hovercraft, mostly of 5К4 design. That accounted for 25% of the total number of carried people. The share of hovercraft in passenger transportation rose to almost 50% by 1978. To a certain extent, that was driven by the commissioning of French ships of Naviplan type from mid-1977. Those 400-passenger ships able to carry 45 passenger cars are currently the largest hovercraft worldwide. Naviplan 500 has a weight of 260 tonnes, calm water speed of 75 knots and capacity of almost 12,000 kW.

    Russia’s civil shipbuilding industry produced no heavy hovercraft. There was a great obstacle in development of this segment – absence of locally manufactured engines with the required characteristics. The problem of power plant’s fuel efficiency was hard to solve even for river-going ships of the above-mentioned Sormovich type. Therefore, the cost of transportation was very high so the ticket price was comparable to transportation by air.

    In Russia, hovercraft failed to become a commercial product. To commercialize such a service, production of hovercraft should be upgraded to ensure manufacture of large series. The larger the series, the lower the unit price. Ships of this type should be built of modern materials with low weigh and high strength characteristics. Power plants for hovercraft, just like for airplanes and helicopters, should meet international standards of reliability, safety, efficiency and environmental sustainability. After-sale service is an important aspect. It low level caused high price of air transportation.

    Tourism is being considered as one of the promising segments of hovercraft application in Russia. Representatives of Water Communications University, Professor V. Shishkin, and V. Okunev, associate professor, Candidate of Technical Sciences, are looking into the routes along the Neva river and across the Gulf of Finland between Saint-Petersburg, Peterhoff, Strelna and Kronshtadt. Ships of Meteor type have been traditionally used on these routes but their navigation season begins in May and ends in September.

    Cayman. Image source: Wikipedia

    Today, 17 shipbuilding companies produce hovercraft in Russia. Most of them are in Nizhny Novgorod including AKS-Invest which builds Mars-700/1000/3000, Aerohod (Hivus-6/10/32/48, А-20), AMFITEX ( Slavir-525/636/936), Aerojet (ASVP Pegas ASVP AEROJET-6М, ASVP AEROJET -8М ASVP AEROJET-11 ASVP AEROJET-14Т ASVP AEROJET-17 ASVP AEROJET-20Т ASVP Pegas-Poseidon), Rospromresurs including its Moscow subdivision (Mirazh-7/11/18), Aerostayer (Strelets type), and Extreme-Motors (Cayman-10). The second largest location of hovercraft production is Saint-Petersburg with its Neptune Design Bureau (Irbis-5, Pardus, Yamal-730 and Razvedchik-660), Christy-Hovercraft (Christy-6143/6184, Christy-Arctic), Shipbuilding Firm “Almaz” (Irbis and Rys). Neptune has its branches in Moscow and Podporozhye of the Leningrad Region. It builds Neptune-11/15/23. There is also a shipyard in Podporozhye which builds Gepard and Puma which are also manufactured in Dolgoprudny by Neptune-Sudomontazh. Omsk based TPC SibVPKNeftegaz builds ships of Arktika type. Khabarovsk Shipyard builds ships of Murena type, Yaroslavl Shipyard – Bars and Chilim. Neptune Design Bureau is and acknowledged leader of hovercraft construction. Besides, Rybinsk based shipyard “Vympel” builds Haska-10 ships for military and civil application. The commercial version of this ship is intended for the oil and gas segment. Its construction is foreseen by the federal programme “Development of Shipbuilding and Equipment for Offshore Fields in 2013 – 2030”.To ensure uninterrupted transport communication in the Far North, some projects of military hovercraft will be converted into civil ones.

    Full-scale serial production of hovercraft is organized by Neptune, Aerohod, AMFITEX and Christy-hovercraft.

    As for seasonal transportation on Volga in Samara, Aerohod hovercraft drove out aero sleigh designed by Tupolev. In Siberia, hovercraft are welcome but they wait for a model to be economically efficient for passenger transportation. Aerohod has already built 1,000 vessels of different capacity. Some of them were exported. USSR had the largest fleet of military hovercraft. Such ships are used for passenger transportation, emergency response and border services. According to the statistics, 85% of all hovercraft in Russia are owned by state structures and their operation is not very intense.

    Yet, what are their prospects in the commercial segment?

    According to the expert opinion of propulsion engineer Vladimir Gerasimov, Samara National Research University, who did military service on Murena hovercraft, such ships can compete economically with helicopters on short routes like crossing of large rivers, bays, etc. Vladimir Gerasimov emphasized that intense civil operation has revealed some problems related to reliability of some systems as well as to repair and prompt delivery of spare parts. Some cases revealed issues of general power plant reliability. Unfortunately, domestic design bureaus do not resolve such problems today. Even issues related to modernization of Murena were not solved. According to Vladimir Gerasimov,  introduction of hovercraft into daily civil operation is even more challenging than designing or production of hovercraft. To address this task an advanced operator is needed and an unsubsidized route so that operation results could be used to justify reasonability of hovercraft acquisition. Vladimir Gerasimov also mentioned the problems of selecting a power plant. In his article published by Engine (edition No 3, 2016) he underlined that energy consumption of hovercraft was exceeding the success of gas turbine construction. The question of what is better, gas turbine or diesel, is still open. According to the expert, one of the priorities is the construction of a reliable reduction unit (regular breakdown of that unit caused the Sormovich programme disruption).

    Victor Sokolov, Chief Designer at Krylov State Research Center, says that one of the key problems related to efficiency of hovercraft is the material for a flexible sealing system. It is the flexible skirt that lets hovercraft pass obstacles including ice which can be rough especially on Siberian rivers. The material wears out quickly and that was one of the reasons behind termination of the Nizhny Novgorod – Bor route on the Volga river. Meanwhile, hovercraft are better for Siberian rivers, especially Lena, than hydrofoils because the latter ones cannot approach undeveloped beaches and require special berthing facilities along the route while hovercraft do not need any. Besides, a challenging aspect is still a power plant with required endurance and fuel efficiency. Hydrofoils have the same problem as they are currently fitted with engines of foreign origin. As of today, their supply is hindered by the international sanctions.

    To ensure successful development of the hovercraft segment development it is necessary to conduct research works in the field of technologies and materials which are a basis for construction of both vessels and engines. Besides, it is necessary to conduct a study for finding design solutions ensuring optimization of weight and durability characteristics.

    By Peotr Kraposhin

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