In writing this final paper, every interactional possibility should be sought to achieve a positive effect regarding the application of a medium-speed engine on ships by applying methods and procedures that can give optimal results in the given circumstances. Therefore, it remains imperative in the present and in the future to explore new ones. the ways of using and applying a medium - speed marine engine for propulsion is an important aspect of space utilization, eg ferries, ro - ro ships, supplers, etc. Regulations regarding the application and use of a medium - speed marine engine should be freely supplemented by practical needs. Initiative legislation in the global and local sense to test ship missions in the world's seas must further encourage research into the development of models and ways of applying and using medium-speed marine engines. After introductory considerations and the introduction of the topic, the definition and basic features of internal combustion engines are given, and then the author presents the latest achievements related to the development and application of medium-speed marine engines. The second part of the paper provides an overview of work operations related to medium-speed marine engines. In this regard, the author offers several practical suggestions.