Abstract: A heat exchanger is an equipment which transfers energy from a hot medium to cold medium when both the mediums are separated by a wall like structure. It is critical for heating and cooling a variety of media during the operation of many onboard services and systems. This study represents different types of heat exchangers used in ships. Here, it has been given emphasis on the shell, tube and plate type of exchangers along with literary reviews and onboard ship. The applicability of various types of heat exchangers at different situations and environmental conditions has been explained. This study, thus, provides an overview of different types of heat exchangers with special reference to onboard ships.