In this thesis, the mode of functioning of maritime DC microgrids is described. The basic concepts of direct current distribution have been elaborated, which includes the very definition of microgrid, and the advantages and disadvantages of using direct current distribution over alternating current distribution on board. Speaking of microgrids, uses of microgrids outside of maritime activity is explained, as well as their control scheme. Switching techniques of direct current distribution and various types of switches are described. Furthermore, battery energy storage was considered as one of the ways of navigation. The thesis also elaborates on the topic of energy converters as a way of transferring energy. The methods of connecting the ship's direct current networks with land systems are defined, each of which has its own advantages and disadvantages. Conclusion elaborates the current situation as well as the future of direct current distribution in maritime affairs. The conclusion also summarizes the entire paper in a concise manner and provides a general picture and overview of maritime DC microgrids.