Advantages of Sonar systems in Various Technological Interest in the seas and oceans and in what goes on underwater has grown rapidly in recent years, and in many countries a very large amount of money is spent in oceanography and fisheries work of a vast variety. Some of this interest arises from the difficulties which traditional fisheries are existing nowadays from the need to obtain more food from the sea while fish stocks seem to become less, some arises from the needs of communication, some from the search for new supplies of oil, some from military and naval needs, and some of the interest arises from human curiosity that the need to understand our environment which is inborn in intelligent human. Projects are started to the direction of these goals, and many inventions have been discovered about observing underwater techniques. Although there are more inventions about maritime, the most useful invention of the world is sonar systems that can be used in many technological branches as fisheries research, oceanography, navigation and military operations. Before the sonar systems, fishing is entirely depended on fortune. Fish shoals were discovered and were caught by the skippers experience and fortune. It was not a regular system. Because of that, sea was not seen as an income source. These problems disappeared after sonar systems are invented. Then, sonar systems become an important helper for fishermen to detect fish shoals. Now, they do not spend so much time for detecting, and they can use fishing charts to learn which area is more suitable for fishing . Therefore, sonar systems have been milestones in the fisheries research. Presumably, if it were possible, a fishing skipper would like ideally a complete, immediately up-to-date, immediately available map of the whole fishing area showing the exact location, extend, density, depth, movement, species and size of all fish shoals, together with details of the sea bottom such as depth, contours, slopes, stones, rocks. Of course, there was not any technology to get these information at the beginning of the nineteenth century. Sensations and experiences of skippers were very important before the sonar systems. Skippers were able to draw up a map by their experiences. But, it was only very crude information. Experience will tell the skipper which area might be profitable to fishing, but he cannot know beforehand whether worthwhile concentrations of fish will be there. Therefore, fish shoals were discovered by the sensations of skippers. Getting complete information on species of fish, size of fish and their density in the shoal is provided easily and quickly with sonar systems. It can be observed at some distances and the net can be made ready before the shoal comes. In addition, the ship or the trawl can be damaged in toothed areas. Therefore, sonar systems can be used to locate toothed areas of ocean bottom .“It has a range 1,600 ft. and is, presumably, effective throughout that range.” It is necessary in this case know not only where the fish are but also to be able to set the net at the right depth. Observing the shoals that are under the ship can be observed with echo sounder. It can only detect the shoals that passing underneath the ship, but sonar systems can detect them at any angle. Norwegian scientists solved this problem by using metal mirror. Fishermen can establish fish shoals that exist suitable depth in the sea, with a recording echo sounder. It gives information about fish shoals and properties of ocean bottom. Nevertheless, it writes down the information to use it following years . Behaviours of fish in the moving nets, how many fish escaped or hurt, can be easily determined. Another using area which sonar systems can be used, is oceanography. Oceanography is the study of the seas and oceans in all its scientific aspects. In its biological side, oceanography includes the study of numero [Ödev İndir]