K ullan ld ilk y llarda büyük ilgi gören, fakat beklentileri yeterince

AIR CUSHION VEHICLES: HOVERCRAFTS HAVA YASTIKLI TEKNELER: HOVERKAFTLAR K ullan ld ilk y llarda büyük ilgi gören, fakat beklentileri yeterince karfl layamay nca bir yana b rak lan hoverkraftlar, yeni teknolojilerle ve ortaya ç kan yeni kullan m alanlar yla flimdi yeniden gündemdeler. Askeri alanlarda da hem karada, hem denizde ayn h zla gidebilmesi aç s ndan çok büyük önem tafl yan hoverkraftlar, ngiliz Kanal n n çevresinde bir feribotun 90 dakikada katetti i mesafeyi 35 dakikaya kadar indirebiliyor. lk ortaya ç k fl ndan bu yana gerek güç, gerek flekil bak m ndan oldukça geliflip de ifliklikler gösteren hoverkraftlarla ilgili olarak Tübitak - Bilim Teknik dergisi yazarlar ndan Sosyolog Gökhan Tok; Hoverkraft; araç ile zemin aras ndaki havada, d fl havaya göre oluflturulan farkl bas nc n (hava yast ) tafl ma etkisine dayal hareket eden, karada ve denizde de gidebilen bir tafl t olarak tan mlanabilir. diyor ve devam ediyor: Baz hava yast kl araçlar bas nç fark n, ancak ileri do ru hareket ederken, baz lar ise ileriye do ru harekete ba l olmadan da oluflturabilirler. ngiliz Sir Thornycraft, hava yast kl araçlar n ilk tasar mc lar ndan biri olarak kabul ediliyor. Thornycraft, 1870 lerde gövde bölümü bas nç odas biçiminde olan bir teknenin (gerçekte taban aç k bofl bir kutu) bu bölmesine hava pompaland nda, teknenin suyun üzerinde yükselece ini ve sürtünme azalaca için h zl hareket edebilece ini ileri sürdü. Bu düflüncesini, gelifltirdi i modeller üzerinde denedi ve 1877 de bunlar n patentini ald. Ald ama, Thornycraft, oluflturulan hava yast n n teknenin alt ndan s zarak d flar kaçmas sorununu çözemedi. Bu sorun nedeniyle de uzun süre istenilen nitelikte hoverkraftlar gelifltirilemedi. 1950 lerde ngiliz mucit Christopher Cockerell sorunu aflt. Cockerell, düflündü ü araç için kar s n n saç kurutma makinesiyle ve teneke kahve kutular yla deneyler yap yordu. Bu deneylerin sonucunda bugünkü hoverkraftlar n ilk örne ini yaflama geçirdi. SR.N1 ad n vermeyi tasarlad bu araç, hem denizde hem de karada gidebilme O riginally called Hovercraft, these vehicles that attracted great attention during the first years of their use but were set aside when they did not fulfill expectations are now back on the agenda through new technologies and new areas of use as revealed. Hovercraft is a vehicle that moves based on the carrying effect of the differential pressure (air cushion) generated in the air between the vehicle and the ground with respect to the external air and which can travel on both land and sea. Some vehicles with air cushion can generate the differential pressure only while moving forward, and some without being subject to a forward movement. Sir Thornycraft, an Englishman, is considered one of the first designers of air cushion vehicles. Thornycraft claimed during the 1870s that, in a vessel with a body section having the shape of a pressure chamber (in fact, an empty box with an open floor), if air is pumped through this section, the vessel would rise on the water and, since friction is reduced, it would be able to move fast. He tested his idea on the models he developed, and obtained the patent of these in 1877. Indeed he did, yet Thornycraft could not solve the problem of air escaping 050

The idea of a vehicle which can travel on both land and sea is very old; however it has been turned into reality only recently. The design and implementation of this idea was not until the mid-20 th century. Hem karada, hem denizde gidebilen bir araç düflüncesi oldukça eskiye dayan yor. Orjinalinde hovercraft olarak adland r lan bu teknelerin tasarlanmas ve hayata geçirilmesi 20. yüzy l n ortalar na rastl yor. özelli iyle benzersiz olacakt. 26 Temmuz 1959 da bu düflüncesini gerçeklefltirdi i ilk modelini denedi ve baflar l oldu. Cockerell, bas nç odas yerine, teknenin alt bölümünün çevresini afla do ru hava püskürten borularla donatt. Bunlar hafif biçimde içeri do ru e ikti. Böylece püskürtülen hava, teknenin alt nda toplan p bas nç yaratarak gövdenin yükselmesini sa layacakt. Ayr ca güçlü hava jetleri teknenin alt bölümünü çevreleyen bir perde oluflturacak, bu perde içerideki hava yast n n d flar kaçmas n engelleyecekti. Tasar ma göre gerçeklefltirilen ilk hoverktraft olan SR.N1, 1959 da suya indirildi. Bu ilk model ancak üç yolcu tafl yabiliyordu ve modelin tek eksi i düflük yolcu kapasitesi de ildi. Bunun yan s ra, yaln zca sakin sularda ya da düzgün yatay zeminlerde çok düflük h zla güvenli hareket edebiliyordu. Asl nda bu arac n Cockerell in özgün tasar m ndan farkl bir yan vard. lk düflündü ünün tersine, çevresel hava jetlerinin hava yast n içeride tutmaya yetmedi i anlafl lm flt. Bu nedenle teknenin çevresinden afla do ru kauçuktan yap lm fl bir etek as lm flt. Ete in bafll ca üstünlü ü, hava yast n engebeli arazide ya da dalgal sularda h zla boflalmaktan koruyabilmesiydi. from the bottom of the vessel. Due to this problem, hovercrafts with desired qualities could not be developed for a long period of time. In the 1950s, the English inventor Christopher Cockerell overcame this problem. Cockerell was carrying out tests with the coffee tins and the hair dryer of his wife for the vehicle he was contemplating. As a result of those tests, he brought to life the first example of today s hovercrafts. This vehicle, which he intended to give the name SR.N1, was going to be unique thanks to its capability of travelling on both land and sea. He tested his first model through which he carried this thought into effect on July 26, 1959 and became successful. Cockerell equipped the periphery of the bottom section of the vessel, instead of the pressure chamber, with pipes spraying air downwards. These were slightly concave. Thus, the sprayed air would accumulate beneath the vessel and, by generating pressure, enable the body to rise. Furthermore, the strong air jets would form a curtain which surrounded the bottom section of the vessel and this curtain would prevent the air to escape. SR.N1, the first hovercraft built according to this design, was MARINE & COMMERCE OCTOBER 2007 051

Hoverkraftlar n bafll ca bölümleri; ete in yan s ra, tekne, motor, kald rma ve itme sistemlerinden oluflur. Teknenin yap m nda kullan lan alüminyum kaplama levhalar, yine alüminyumdan yap lm fl çatk ya kaynakla ba lan r. Tekne, kald rma ve itme sistemlerinin her ikisine de güç sa layan bir gaz türbin motoruyla hareket eder. Motorun tekneyi kald rmak için sa lad güç, arac itmek için gereken güce oranla daha fazlad r. Kald rma iflleminde hava, teknenin alt ndaki püskürtme borular na yüksek devirli fanlar arac l yla itilir. tme iflinde ço u zaman hoverkrafta uyarlanm fl jet motorlar ndan yararlan l r. Pervaneler ço unlukla teknenin k ç bölümüne, hareketli çe- engine air intake duct lik kolonlar üzerine yerlefltirilir. Pervaneyle birlikte kendi eksenleri etraf nda dönebilen Gnome engine kolonlar, tekneye ek bir manevra yetene i sa lar. As l yön denetimiyse arac n arkas ndaki kuyruk dümeniyle gerçekleflir. Hava yast n n derinli- i genellikle arac n uzunlu unun onda biri olur. Bundan dolay da hoverkraftlar n kontrolu oldukça zordur ve karayollar nda kullan lamam flt r. ventilation air intake life raft machine gun installation antenna air conditioning cowling radar scanner SR.N1 in gelifltirilmesinden günümüze dek hoverkraftlar n etek sistemlerinde önemli de ifliklikler gerçeklefltirildi. Bafllang çta arac n kenarlar na perde gibi as lan ve kauçuk benzeri malzemeden yap lan etek, h zl seyir s ras nda kara ya da su yüzeyine sürtünerek k sa sürede afl n yordu. Günümüzdeyse bu etekler, dayan kl naylon ve plastik malzemeden yap l yor. Ayr ca bugün, perde biçimindeki ete in yerini arac n alt çevresini saran kal n bir boru biçimindeki torba etekler ald. Hava, torba ete in içeri bakan bölümündeki bir dizi delikten püskürtülür ve böylece arac n taban ile su ya da yer yüzeyi aras nda hava yast oluflurulur. Araç hareket etmiyorken torba ete in üzerine biner. Torba ete in alt bölümünde onu sürtünmeden kaynaklanan afl nmaya karfl koruyan ikinci bir etek bulunur. 1960 lar n bafl nda h zl hoverkraftlardan denizlerde, çöllerde, ya da buzlarla kapl bölgelerde yararlan labilece i düflünülmüfltü. Fakat k sa sürede sorunlar n fark na var ld. Yetersiz etek tasar m ndan ve tuzlu suyun etkisiyle kolayca t kanarak bozulan gaz türbinlerinden kaynaklanan sorunlar önemli güçlükler do urdu. Hoverkraft düflüncesi yaln zca ngiliz mucit Cockerell in zihnini yormuyordu. Bu konuyla ilgilenen baflkalar da vard. 1950 li y llarda Charles Flatcher, Glidemobile ad n verdi i hava yast üzerinde giden bir tafl t tasarlam flt. Hava yast yla kayarcas na yolculuk etmenin bir merakl s daha vard. Frans z mühendis Jean Bertin bu konudaki tasar mlar n gerçeklefltirdi ve bir hoverkraft da o yapt. N500-02 ad n verdi i bu araçla 1960 l y llarda su launched in 1959. This first model could only carry three passengers. The low passenger capacity, however, was not the only drawback of this first model. Also, it could move safely only at very low velocity on calm waters or on smooth horizontal grounds. As a matter of fact, this vehicle had a side different from the unique design of Cockerell. Contrary to what he initially thought, it was understood that the peripherial air jets were not sufficient to keep the air cushion inside. Therefore, a skirt made of rubber was hung from the periphery of the vessel plenum bleed duct downwards. The primary superiority of the skirt was that it was able to petter APU protect the air cushion against a speedy discharge on rough terrain or in wavy waters. SR N6 MILITARY HOVERCRAFT walk way lift fan condenser overload tank side control valve flexible trunk By 1980, 40 of these 10 tonne Winchester class military hovercraft were in service fingers worldwide, from Brunel to Italy, proving their value in coastal and border patrols. Troops and up to five tonnes of equipment can be moved rapidly to trouble spots over a wide variety of services. The major sections of hovercrafts consist, apart from skirt, of a vessel, an engine, a lifting and propulsion systems. The sheets with aluminium coating used in construction of the vessel are welded to a framework made of aluminium similarly. The vessel operates through a gas turbine engine which powers both the lifting and propulsion systems. The power which the engine supplies in order to lift the vessel is greater than that which is required to propel the vehicle. During the lifting process, the air is pushed into the spray pipes beneath the vessel by means of the high speed fans. For the propelling process, jet engines which are adapted to hovercrafts are used by the majority of the cases. Propellers are mostly placed at the aft of the vessel, on the movable steel columns. Columns which can rotate around their own axis along with the propeller provide the capability of an additional manoeuvrability to the vessel. The main control of direction is ensured through the tail steer at the back of the vehicle. The depth of the air cushion usually corresponds to one tenth of the length of the vehicle. Therefore, the control of hovercrafts is very difficult and could not be used overland. Major changes have taken place in the skirt systems of hovercrafts since the time SR.N1 was developed until recently. Initially the skirt which was hung like a curtain on the sides of the vehicle and made of a material similar to rubber wore off within a short time upon rubbing on the land or water surface during high speed navigation. Today these skirts are made of durable nylon and plastic material. Furthermore, the skirt which had the form of a curtain has been replaced by bag skirts having the shape of a thick pipe surrounding the lower periphery of the vehicle. Air is sprayed through a series of holes in the section of the skirt facing inwards, and thus, an air cushion is generated between the bottom and the water or ground surface. When the vehicle is not moving, the bag rides on the skirt. A second skirt is provided at the lower section of the bag skirt which protects 052

üzerinde saatte 137 kilometreye ulaflabilmiflti. Bu bir rekordu. N500-02 nin tek üstün özelli i çok h zl oluflu de ildi. Bertin in hoverkraft na bir jumbo jete s acak kadar yolcu binebiliyordu. Bu araçla 400 yolcu, 55 otomobil ve 5 de otobüs tafl nabilmekteydi. ABD de 60 l ve 70 li y llarda çeflitli hoverkraft denemeleri yap ld. De iflik tasar mlar üretildi. Çeflitlenen bu tasar lara SES (Surface Effect Ship-Yüzey Etkili Gemi) ad veriliyordu. Bunlar daha çok bir katamaran ile hava yast kl bir arac n birleflimi gibiydiler. Bu gemilerde hava yast katamaran n iki gövdesi aras na yerlefltirilmiflti. Bu hava yast devreye girdi inde hoverkraft gibi yükselen araç, suyun üzerinde oldukça yükseliyordu. Bu sayede suyun direncini en aza indiren bu tafl t, yüksek h zlara da ulaflabiliyordu. Bu tür SES gemilerinin hoverkraftlara karfl bir zay f yan vard ; karada gidemiyorlard. Normal gemiler gibi yaln zca suda yüzüyor ve limanlar kullan yorlard. SES gemileri ortaya ç kt dönemde oldukça popüler olmufltu. Öyle ki ABD de SES teknolojisini kullanarak bir filo kurulmas tasarlanm flt. Saatte 180 km h z yapabilecek bu gemiler katamaran olacakt. Hava yast kl dev katamaranlardan oluflacak filo, t pk normal bir donanma gibi f rkateynler, hücum botlar hatta uçak gemileri bar nd racakt. Bu filo için ilk planlanan 8,000 tonluk bir torpido gemisiydi. Bu gemi ayn zamanda 4 F-18 avc uça, dik havalanabilen 4 uçak ve 4 de helikopter tafl yabiliyordu. Bu proje kapsam nda k sa sürede deneme amaçl iki gemi yap ld. Bunlar saatte 174 km h z yapabiliyordu. Fakat proje yürümedi. Denemelerden k sa süre sonra projeden vazgeçildi i aç kland. Sorun teknik olmaktan çok politikti. Pentagon bu konudaki politikas n de- ifltirmifl, klasik gemilere a rl k vermeye karar vermiflti. 60 l y llar n ortalar nda hava yast tekni inin h zl trenlerde kullan lmas denemeleri de yap l yordu. Frans z mühendis Jean Bertin in Havatreni büyük ilgi ve heyecan uyand rd. Yaln zca iki kifli tafl yabilen bir prototip olan ilk model, 22 Ocak 1969 tarihinde yapt denemede saatte 422 km ye ulaflmay baflard. Bundan birkaç y l sonra, Ekim 1973 te 80 yolcu tafl yabilen bir model de saatte 400 km ye ulaflacakt. Gerçekte bu tren normal raylar üzerin- against wear due to friction. Early in the 1960s, it was throught that it could be made use of high speed hovercrafts on sea, deserts or ice-covered areas. However, problems were soon discovered. The problems arising from insufficient skirt design and gas turbines, which were easily blocked and failed upon the effect of salt water, gave rise to major difficulties. The thought of hovercraft did not only preoccupy the mind of the English inventor Cockerell. There were also others who took interest in this subject. In the 1950s, Charles Flatcher designed a vehicle, which travelled on an air cushion and which he called Glidemobile. There was still another person who was anxious to travel by almost gliding through air cushion. The French engineer Jean Bertin carried out his designs on this subject and made another hovercraft by himself. With this vehicle he called N500-02, he was able to reach a speed of 137 kilometers per hour on water in the 1960s. This was a record. Very high speed was not the only superiority of N500-02. Passengers who could well fit in a jumbojet could embark on the hovercraft of Bertin. 400 passengers, 55 cars and 5 buses could be carried board this vehicle. Various hovercraft tests were conducted during the 1960s and 1970s in the USA. Different designs were developed. These diversified designs were called SES (Surface Effect Ship). These looked more like the combination of a catamaran and an air cushion vehicle. Air cushion was placed between the two bodies of the catamaran. When this air cushion was enabled, the vehicle that lifted up like an hovercraft rose a great deal on water. The vehicle that minimized the resistance of the water as such could also reach very high velocities. Such SES ships had a weak side as compared to hovercrafts: They could not move on land. They could float on water and use ports like ordinary ships. The SES ships became very popular during the period they were first launched. It was such that a fleet was contemplated to be established by using the SES technology in the USA. These ships that could travel 180 km per hour would be a catamaran. The fleet that would consist of giant catamarans with air cushion would host frigates, assault boats and even airplane carriers just a like an ordinary navy. First a torpedo ship of 8000 tons was planned for this fleet. This vessel could also carry 4 F-18 fighter planes, 4 vertical-take-off airplanes and 4 helicopters. Two ships were built for testing purposes within a short time within the scope of this project. These could travel at a speed of 174 km per hour. However, the project could not be realized. Soon after the tests, the project was stated to have been laid aside. The issue was more of a political nature than being a technical one. Pentagon had changed its policy in this matter and decided to give weight to classical ships. During the mid-1960s, the tests for the employment of the air cushion technique also on high speed trains were under way. The Air Train of the French engineer Jean Bertin aroused great interest and excitement. The first model which was a prototype capable of carrying only two people achieved to reach a speed of 422 km per hour during the trial held on January 11, 1969. A couple of years after this, in October 1973, a model which was capable of carrying 80 people was going to reach 400 km per hour. In fact, this train did not move on ordinary rails. The line on which the vehicle travelled was a concrete one. At the bottom of the train 054

de gitmiyordu. Arac n yol ald hat, beton bir hatt. Trenin alt taraf nda T fleklinde profili olan bir boflluk bulunuyordu. Bunun ortas nda yer alan beton hat ray görevi görüyor, tren havaland nda bu hatt n üzerinde gidiyordu. Bu boflluk trenin bafl taraf ndan bak nca, a z n açm fl aç bir hayvan and r yordu. çinde yer alan iki pervane havay emiyor ve trenin alt na gönderiyordu. Ekim 1973 te yeni bir deneme yap ld. Denemede arac n ön motorlar dev pervanelerle donat lm flt. I-80 ad verilen bu modelin motorlar nerdeyse bir jet motoru kadar güçlüydü. Bu sayede tren yere temas etmeden ve hiç sars lmadan yol alabiliyordu. Trenin deneme aflamalar nda denek olarak yüzlerce yolcu yer ald. Hava yast üzerinde giden bu trenin içinde yaz yazman n, evde, masa bafl nda otururken yaz yazmaktan fark yoktu. Trenin deneme aflamas nda kullanmak için oldukça uzun bir hat döflenmiflti. Bu hat sonra Paris-Orleans hatt - n n temelini oluflturacakt. Temmuz 1974 de Frans z yönetimi Train a Grande Vitesse (TGV) ad n verdi i h zl tren projesini bafllatt. Eylül 1975 de Paris-Lyon hatt ifllemeye bafllad. Hoverkraftlar ilk ç kt klar nda büyük ilgi uyand rd larsa da sonralar, kendilerine yüklenen beklentileri yeterince karfl layamad klar için ilginçliklerini büyük ölçüde yitirmifllerdi. Kontrollar düflünüldü ü kadar kolay de ildi, s k s k ar za yap yorlard ve çok gürültülüydüler. Bununla birlikte hoverkraftlar n baz kusurlar n n giderilmesiyle bu araçlara ilgi yeniden artmaya bafllad. Örne in Almanya da 1998 y l nda, hoverkraftla tafl nan araba say s nda bir önceki y la oranla %32 lik bir art fl gözlendi. ngiltere, Fransa gibi hava yast yla araçlar üreten ülkelerde de bu rakamlar gün geçtikçe art yor. Deniz tafl mac l nda, özellikle de yolcu tafl mac l nda hoverkraftlar n gelece i parlak görünüyor. H zl tafl mac l n art k gereksinim haline geldi i günümüzde, armatörlerin ve ifl adamlar - n n da hoverkraftlara ilgi duymaya bafllad n söylemek yanl fl olmaz. Bu ba lamda Blohm&Voss flirketi, hoverkraftlar n ticari yönünü ortaya ç karmaya yönelik tasar mlar üzerine çal flmalar n sürdüren kurulufllardan biri. 170 ton kapasiteli ve saatte 92 km h z yapabilecek bir model üzerinde çal flt bilinen flirketin SES Corsair ad verilen teknenin üzerindeki denemeleri hala sürüyor. fiimdiye dek elde edilen sonuçlardan SES Corsair in beklentilere yan t verebilecek bir tasar m oldu u görülüyor. Bu da henüz geliflmekte olan hoverkraftlar n do ru yolda oldu unu gösteriyor. H zl deniz tafl mac l nda üzerinde çal fl lan bir baflka proje de MEKAT s n f tekneler. Bu teknelerin çal flma ilkesi de SES teknolojisine dayan yor. Bu teknelerde hava yast sayesinde gövdenin yaln zca % 20 si su içinde kal yor, geri kalan % 80 i hava yast üzerinde tafl n yor. Böylece MEKAT s n f gemiler suyun engellemesi azald ndan saatte 110 km ye kadar ç kabiliyor. Hoverkraftlar yaln zca deniz tafl mac l yla u raflanlar n ilgisini çekmiyor. Hava yast üzerinde yolculu a en büyük ilgiyi gösterenlerden biri de ordu. Hoverkraftlar, askeri amaçlarla kullan lmak için de oldukça uygun tekneler. H zl olmalar n n yan s ra hava yast klar sayesinde hem denizde hem de karada yol alabilmeleri onlara üstünlük sa l yor. Böylece amfibik görevlerde kullan lmaya uygunlar. Bunun yan s ra ç kartma gemilerinden de daha h zl olduklar için ra bet görüyorlar. there was a gap which had a T-shaped profile. The concrete line which was in the middle of this served as the rail and when the train took off, it travelled on this line. This gap, when viewed from the head of the train, looked like a hungry animal with an open mouth. Two propellers contained within sucked the air and sent it under the train. A new trial was held in October 1973. During the trial, the front engines of the vehicle were equipped with giant propellers. The engines of this model, called I-80, were almost as powerful as a jet engine. As such, the train could travel without contacting the ground and with no shaking effect at all. Hundreds of passengers took part as subjects at the testing phases of the train. Writing on this train which travelled on an air cushion was no different than writing at home, by one s desk. A very long line was laid for use in the trial phase of the train. Later, this line was going to establish the foundation of the line Paris-Orleans. In July 1974, the French management launched the high speed train project named Train a Grande Vitesse (TGV). The Paris-Lyon line was commissioned in September 1975. Although the hovercrafts aroused great interest when they were first launched, they largely lost their popularity since they failed to properly fulfill the expectations burdened on them. Nor was their control as easy as was once thought; they often failed and were too noisy. Yet, upon the elimination of the certain faults of hovercrafts interest rose again towards these vehicles. For example, in Germany in 1998, a 32% increase was observed in the number of cars carried by hovercrafts as compared to the previous year. This figure is on the rise also in the countries manufacturing vehicles with air cushion such as the Great Britain and France. In maritime transportation and especially passenger transportation, the hovercrafts seem to have a promising future. In recent times when high speed transportation has now become a need, it would not be improper to state that shipowners and businessmen have also become interested in hovercrafts. In this connection, the company Blohm&Voss is one of the institutions carrying on activities on designs aimed at revealing the business aspect of hovercrafts. This company has been working on a model with 170 tons of capacity and which can travel at a velocity of 92 km per hour for a few years. Trials on the vessel called SES Corsair are still under way. According to the results so far obtained, SES Corsair seems to MARINE & COMMERCE OCTOBER 2007 055

The sea buses are the modern versions of the hovercrafts and they have been in use in Turkey since the 1980s. These crafts are still quite important with respect to their speed and for they alleviate the burden of the city line ferries in Istanbul. Hoverkraft teknolojisine karfl son y llarda artan ilgiden Japonya da pay n düfleni alm fl. Japon Mitsui flirketi üç de iflik tasar m yla önde gelen flirketlerden. Tasarlad klar en büyük teknenin 1,500 yolcu tafl yabilecek ve saatte 80 km h z yapabilecek özelliklere sahip olaca ifade ediliyor. 127 metre uzunlu undaki bu hoverkraft, ngiltere de bulunan dünyan n en büyük hoverkraft n n 2,5 kat büyüklü ünde. Teknenin Japon kentleri aras nda sefer yapmas düflünülmüfl. HOVERKRAFTTAN DEN Z OTOBÜSÜNE Araflt rmac yazar Tok a göre, hoverkraftlar n günümüze uyarlanm fl ve 1980 li y llardan beri Türkiye de de kullan lmaya bafllanm fl versiyonlar deniz otobüsleri. Bu araçlar, özellikle stanbul da flehir hatlar vapurlar n n yüklerini hafifletmeleri ve h zlar nedeniyle de hala önem tafl yorlar. stanbul Deniz Otobüsleri ( DO) A.fi. nin makine enspektörlerinden, Gemi Makine flletme Mühendisi Levent Elo lu Marine&Commerce dergisi için yüksek h zl tekneleri, tekne yap tiplerinden yola ç karak; bu kapsam dahilinde gelifltirilmifl yüksek h zl tekneler; hava yast kl tekneler yani hoverkraftlar (ACV), kald r c ayakl tekneler (Hydrofoil), tek gövdeli ve çok gövdeli tekneler (Monohull, Catamaran, Trimaran, Quadrimaran), yüzey tesirli tekneler (SES), yüzey etkisinde uçufl tekneleri (GEC- Ground Effect Craft) olarak s n fland rd. stanbul Deniz Otobüsleri, yüksek h zl gemi filosunda yer alan tekne formu yap lar ndan, simetrik katamaran tipi uygulanm fl ve de iflik tahrik yöntemleri kullan larak, yolcu ve araç tafl yabilme kapasitesi kazanm fl bir filoya sahip. DO nun markalaflma yolundaki at l mlar nda bu katamaranlar n rolü de oldukça önemli. & Hoverkraftlar n günümüze uyarlanm fl ve 1980 li y llardan beri Türkiye de de kullan lmaya bafllanm fl versiyonlar deniz otobüsleri. Bu araçlar, özellikle stanbul da flehir hatlar vapurlar n n yüklerini hafifletmeleri ve h zlar nedeniyle de hala önem tafl yorlar. be a design which can meet the expectations. This indicates that the yet developing hovercrafts are on the right route. Still another project worked on for high speed maritime transportation is the vessels of MEKAT class. The operating principle of these vessels is also based on the SES technology. Thanks to the air cushion in these vessels, only 20% of the body is submerged in water and the remaining 80% is carried on air cushion. Thus the ships of MEKAT class can attain a speed of 110 km per hour since the water obstacle is reduced. Hovercrafts do not only attract the interest of those involved in the maritime transportation. Army is one of those showing the greatest interest in travelling on air cushion. Hovercrafts are also highly suited for use for military purposes. In addition to having a high velocity, their capability to travel on both land and sea gives them superiority. As such they are suitable for use in amphibic operations. Additionally, they are popular since they have greater speed compared to the landing crafts. Japan has also taken its share of the recently soaring interest in the hovercraft technology. The Japanese company Mitsui is one of the leading companies with its three different designs. The largest vessel it has designed will be capable of carrying 1500 passengers and travelling at a speed of 80 km per hour. This hovercraft that is 127 meters long is 2,5 times the size of the largest hovercraft in the world, which is in the Great Britain. This vessel has been designed to provide services between the Japanese cities. During the 1980s hovercrafts started to be used also in Turkey. These vehicles, known as Sea Bus, have alleviated the burdens of especially the city line ferries in stanbul. They are still very popular because of their high speed. Some forty years have passed since the day the hovercrafts had their first voyage in the English Channel. During a show organized in May 1999 in Great Britain, their home country, designs of more than 40 hovercrafts were exhibited. FROM HOVERCRAFT TO SEA BUS... According to Tok, the sea buses are the modern versions of the hovercrafts and they have been in use in Turkey since the 1980s. These crafts are still quite important with respect to their speed and for they alleviate the burden of the city line ferries in Istanbul. Levent Eloglu, Ship Engine Operating Engineer, an engine inspector of the Istanbul Sea Buses and Fast Ferries, Inc. (IDO), classified the high-speed crafts for the Marine & Commerce Magazine: Based on the hull types, the high speed crafts developed within this scope are air-cushion vehicles, in other words hovercrafts (ACV), hydrofoil boats, Monohulls, Catamarans, Trimarans, Quadrimarans, Surface Effect Ships (SES), and Ground Effect Crafts (GEC). The Istanbul Sea Buses and Fast Ferries, Inc. has a fleet of highspeed crafts of symmetrical catamaran type, and these crafts are capable of carrying passengers and vehicles through use of different propulsion methods. Indeed, these catamarans play a very important role increasing the brand valuation of IDO. & 056