In this final paper, the influence of corrosion on the ship is described, and corrosion protection methods are presented, and in particular the method of cathodic protection is described. Corrosion is a well-known problem that has been occurring in the maritime sector since the ships themselves. A lot of attention is paid to corrosion protection due to the fact that many ships failed due to inadequate corrosion protection and large financial losses were suffered. The paper contains six parts. In the first introductory part of the paper, the topic of the paper is presented and the subject of the paper is briefly explained and the structure of the paper is presented. The second part of the paper theoretically explains the concept of corrosion. The third part of the paper presents the types of corrosion. The fourth part lists the requirements for ship protection according to the rules of the Croatian Register of Shipping. The fifth part of the paper refers to cathodic protection where cathodic protection procedures are explained in detail and examples of its application on board are given. The sixth part contains conclusions in which the facts that were reached by making this final paper are presented. Each part of the paper is explained theoretically and in addition, appropriate images were presented.