A heat exchanger integrated to the central cooling system is used to cool the main engine in ships. Central cooling system serves a "sea water based" cooling option. The main focus of this study is to analyze the prospect of the shipboard to be used as a heat exchanger. 3-D CFD analysis (StarCCM+) results are compared with the results obtained by the SPH method implementing explicit time integration. The problem is also approached analytically by making certain assumptions and there is about 3% difference between the analytical and the numerical results.