Conceptual design of a tourist submarine which operates in shallow waters and short distances

Underwater life and objects of a region provides considerable information about ecosystem, history and culture of this particular place. Underwater life and underwater itself have always been regarded as mysterious and arouse curiosity in people due to its relatively restricted accessibility and consequently lack of information. For this reason, exploitation of underwater resources for touristic purposes is becoming more and more popular. Hotels built underwater, aquariums, scuba diving, semi submersible vehicles and tourist submarines are some of the opportunities that the underwater tourist industry provides. The word `submarine' usually recalls military type submarines to one's mind. Since, compared to military applications, submarines for entertainment or scientific purposes have relatively recently become popular, available sources for their design and construction are quite scarce. Restricted access to information on military type submarines makes the accessibility problem severer and even more limited. The most important feature that distinguishes a tourist submarine from a military type submarine is the relatively quite many windows allowing observations with naked eye in underwater environment. This important difference naturally poses considerably engineering challenges which cannot be readily solved. Design of touristic submarines is a relatively new subject in Turkey with, to the best of our knowledge, no previously reported work. At present, it is estimated that there are about 30 tourist submarines that are being used in various parts of the world. In Turkey the one and only tourist submarine, which was imported, started to operate at Antalya Kaleiçi in March 2017. The underwater objects experience a pressure around them, which is proportional to the height of the water level above them. This pressure is called hydrostatic pressure. The hydostatic pressure is the dominant force underwater. Therefore, it is expected that a vessel working underwater must be designed to withstand the hydrostatic pressure it is subjected. In the design of a touristic submarine, the windows impair the strength of the ship to withstand the hydrostatic pressure that increases with depth. Therefore, the dimensions and number of observation windows basically limit the allowable depth the passengers can be carried. Hydrostatic pressure acting on an object forces it to collapse upon itself. For this reason, an object with the highest durability to the hydrostatic pressure is in a form of sphere. Presently, there are tourist submarines that are able to dive as deep as 3,000 meters though these submarines are quite few in number. A company aims to be able to dive into the deepest point of the ocean, the Mariana Trench, with its new model. The depth of Mariana Trench is about 10,994 meters. But, all these designs are submarines that are small enough to provide up to one or two people in. The cabins are transparent and designed to be in the closest form to a sphere. In this study, conceptual design of a touristic submarine, which can work in shallow waters and close distances, is considered. The design considered here falls within the category of relatively large touristic submarines. The touristic submarine conceptually designed here has 36-passenger capacity and 50-meter operational depth. The method of the selection of number of passengers and operational depth is clearly explained in the relevant part of the study. From the practical point of view it is not possible to design a submarine with 36 passengers in the form of a sphere. Besides, the hydrostatic pressure at operating depth of 50 meters does not force the design to be in spherical form. A complete design of the submarine which specifications described above, can be achieved through the cooperation of different disciplines and expertises. So the desired tourist submarine can reach its final shape. Naturally, this is possible only with quite extensive work. Here, however, the basic design concepts are considered from the point of view of an ocean engineer. Hence, this is a conceptual design work which is undertaken mainly to provide a basis for more comprehensive future works in the area. As already indicated, the touristic submarine is a relatively new concept in Turkey. For this reason, there are neither rules for their design nor laws for their operation. Therefore, as a preliminary, rules, regulations and laws for other recreational water vehicles and ships are examined. The conceptual design has been carried out by following laws and rules suitable for underwater vehicles and ships. "Technical Regulations of Vessels" published by Turkish Undersecretariat of Maritime Affairs and rules of Turkish Loyd about submarines are used. In addition to these, dimensions of submarine internal volume are determined and calculated with the aid of ergonomics. With the knowledge and the experience of Shipbuilding and Ocean Engineering, other relevant calculations are completed. Dimensions of different parts of internal volume, volume of the cisterns, size of viewing windows, the form, maneuverability and propulsion capabilities, stability values of the tourist submarine are calculated and using results final three dimensional form is achieved. In summary, the conceptual design of a touristic submarine with 36 passengers, 2 crew and 50 meters operation depth has been carried out. Drawings and diagrams that the study includes is expected to provide a basis for a complete final design. While detailed explanations and designs of some features are given, only the maximum and minimum limits of some others are indicated to help possible future works.