It is necessary to maintain the operating temperature for each internal combustion machine to function properly. Excessive engine heating can cause serious damage to the machine itself, and sometimes the engine failure can be dangerous to the environment but also to human lives. To keep the engine running smoothly at the optimum temperature it is necessary to drain excess heat from the engine and this is most often achieved by the heat exchangers. However, for the correct selection of the heat exchanger, it is necessary to know parameters such as engine power, engine operating temperature, seawater flow and it is necessary to know some of the environment in which the vessel will be used. In practice, designing and developing heat exchangers often use complex computer programs for mathematical modeling of flow fields and temperature distribution in pipes. The goal is to get as much heat change as possible, to reduce pressure drop, to make the compact and cheaper construction, and very important, option for cleaning and maintenance.