Master thesis "Cooling system design for a bitumen transport ship" shows the difference between direct and indirect cooling system with an emphasis on the indirect system whose method of cooling individual parts is explained in more detail. The most attention is paid to central cooling system and all its essential elements. The heat balance is also shown on the example of a given ship for the transport of bitumen built in the shipyard "3 MAJ" according to whose data a calculation was carried out, which determined the necessary diametars of pipelines, pumps and heat exchangers. During the development of the scheme, implementation of calculations and simulations, the AFT Fathom program was used based on the example of the ship's cooling system from the shipyard that is previously mentioned. Finally, the flow results obtained by simulation were compared with the predicted flows from the heat balance. The overall analysis determined that the data obtained in the AFT Fathom program deviate from the predicted results from the heat balance, and the reasons for such deviations are explained in more detail in the last part of the paper.