Yelkenli teknelerde tasarım prosedürü

Karataş, İbrahim
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Fen Bilimleri Enstitüsü
Yelkenli teknenin tasarım problemi, dünyada halen popülerliğini korumakta olup, pek çok ülkede ve son yıllarda.ülkemizde de çeşitli biçimlerde görülmektedir. Türkiye'de henüz yapılmamış olan bu tasarım yöntemi çalışmasında, genel çerçevesiyle yelkenli yat kavramı kronolojik gelişimi ile birlikte tanımlanmıştır. Yelkenli teknede denge kavramı, aerodinamik ve hidrodinamik kuvvetlerin oluşumları ve tekne üzerindeki etkileriyle açıklanmıştır. Tasarım sürecinin ve tasarımın elemanları birbirleriyle ilişkilendirilerek, örnek tasarım resimleriyle sunulmuştur. Çoğunlukla karşılaşılan tekne tipi olan gezinti yelkenlileri ön planda tutularak açıklanan tasarım süreci ve elemanları, aynı zamanda bu grubun dışındaki tekneleri de kapsamaktadır. Yelkenli teknelerde oldukça büyük önem taşıyan endaze, yelken planı ve ağırlık dengesi tasarım yönteminde özellikle vurgulanmış, salma tasarımı konusunda verilen bağıntılarla buna ilişkin yöntem de açıklanmıştır. Performans hesabı ile tasarımı tamamlanmış teknenin tasarım isteklerini ne ölçüde gerçekleştirebildiği görülür. Burada kurulan teoride yarış teknesine göre basitleştirmeler yapılmış, ancak teorinin genel yelkenli tekne kavramına uygulanabilmesi için gerektiği yerde açıklamalar sunulmuştur. İzlenmesi öngörülen tasarım prosedürü ile genel hatlarıyla, herhangi bir yelkenli tekne tasarımı yapı İması mümkündür.
The design and construction of sailing boats in Turkey has been subject to considerable development in the last decade. Both the financial and other support provided by the governments and the interest shown in "goullette" and "tirhandil" type boats with their classic-modern characteristics by the foreign yachting enthusiasts have increased the potential of the commercial yachting. The sector, activated. by these factors, has shown significant increases in the number of new boats being built. However there is no established criteria either from engineering or aesthtetic point of view in the concept of yacht design or construction. It is because of this reason that the current yacht building potential is governed by the owners at one end and the builders at the other end, who are skilled but otherwise unqualified from engineering point of view. The result are yachts which do not fulfill the purpose, which are unconf ortable, aesthtetical ly unsatisfactory and even unsafe. These aspects of the state of the yacht building sector prove the need for a study to establish the standarts of yacht design. Hence, in this study, the yacht concept is defined with its general characteristics and a design procedure is given taking into account the parameters which have to be satisfied by a yacht nowadays. XI Various rigging and hull forms are introduced in their chronological order in Chapter 2. The years 4000BC in the time when comes across the concept of ' a sailing hull. Originating from China and Egypt sailing boats began to appear in the whole of the Mediterranean. These first examples could only "run" downwind, i.e. sail in a following wind. This type of sailing boats appeared contemporarily in China, Egypt and South America. For a long time this characteristics of the first sailing boats remained untill the Arabic sailors developed the "lateen" sail which allowed sailing in directions other than that makes an angle of 180 with the wind. In the 14th century, when merchant sailing boats were common in North Europe, small and fast sailing boats began to be used against the pirates by the Dutch, called "jachts". This word has since been used by the English as "yacht", describing the cruising and racing sailing boats. Today's designers find their best opportunity to join engineering and aesthetics in their efforts to obtain sailing boats in this group which is in constant development in line with increasing number of classes and racing clubs. Along the coasts of Turkey, on the other hand the "chektirme", "goulette" and the "tix-handil" are the types of sailing boats that are seen most often, although their sailing characteristics are mostly unsatisfactory and inefficient. The third Chapter is devoted to the fundamental aspect of the aero-hydrodynamics of sailing principle, namely the "balance" of a sailing boat. The aerodynamic and hydrodynamic forces acting on the hull are separately considered for running and reaching conditions. Together with the weights and XII hydrostatic forces, there are four groups of forces to be investigated. These four groups of forces show the different properities depending on whether the boats 'is running downwind or reaching upwind. The course angles, between these two extremes show similar characteristics. The reaching condition is the most important point of sailing from the point of view of speed and motions executed. This fact leads to a comment trend which regards the reaching performance of a boat the criterium of the success of its designer. When investigating the aerodynamic and hydrodynamic force components during reaching, the underwater hull form and various appendices assume significance due to their resistance and lateral force or side force produced due to leeway. Therefore, the designer aims at obtaining a keel which produces high lift to drag ratio at small angles of attack which corresponds to small leeway. Also, center of gravity of the keel must be as low as possible to produce the required restoring heel moment. Chapter four describes. the general boat design under two haedings; the "preliminary design" and the "design". Every stage of the procedure is defined taking into account the interrelationships with the other stages of design. The order with which the design is developed is reflected in the order the elements of the design procedure presented here. In the preliminary design, owner and the designer join forces to agree on the fundamental characteristics of the boat such as speed, comfort, stability, reliability etc. Before starting the design of a sailing boat, the concept of "the boat to be designed" must be evaluated. She can be a weekend cruiser, a small yacht which has a single cabin, a house-boat, an ocean cruiser or ocean racer in a specified class or a very special type of boat. The variety range of the boats to be Xlll designed is extremely wide. But at the end, this is a kind of engineering problem which can be expressed in terms of speed, stability or race regulations etc. Therefore the owner's initial descriptions or the defined purposes of the boat to be designed, are the base for starting the design itself. Problem has two components; special requirements and common requirements. Sometimes special requirements can be placed in far forward of the common requirements. At that situation the designer is the key to evaluate the contradictive requirements andto find the acceptable solution for most reasons. Parallel to that "proposal" is prepared in the form of a drawing which suggest the order of priorities of the selected characteristics. Following the acceptance of the proposal, the design starts and it is executed in the order given in Table. 4. 2. The hull form, general accommodation, sail plan, rigging and the construction drawings are the main elements of the design. However, as shown in Table. 4. 2. there are other drawings required to complete the design. The keel and rudder design analises the procedure as explained in Section. 4. 3. 16 in detail. At this stage the drawings are prepared which define the keel and rudder with sections, profile views and locations to the hull. The strength studies on the attachments for the keel as well as the rudder are completed and included in the construction drawings. After completion of the design of the boat, a performans prediction method is presented in Chapter. 5. Using this method of prediction, it is quite possible to see the success of the design/Obtained results of the prediction method will give reliable comparison between the requirements at the beginning and the actual completed design. xiv The performans of the result boat, in other words obtained speed, heel angle and leeway angle of the boat in different wind direction, speed and angle when sailing will be compared with the preliminary- requirements. If the comparison results are unsatisfactory, the method given in Chapter 4.3.16 should be followed for designing different keel configurations. The same modification track should be applied for the next changes in the design until the satisfactory results are obtained. The order of the design procedure suggested in this thesis provides for a complete sailing boat of any kind with specified characteristics.
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1992
Anahtar kelimeler
Tasarım, Tekneler, Yelkenli tekne, Design, Hulls, Sailing yacht