Marine steam generation plant is used for the production of water steam of desired pressure and temperature and has wide application on board ship, representing one of the most important marine systems, extremely important for the operation of the entire ship power system. The steam is used as a steam turbine working medium and for the transfer of heat to various devices and systems, such as oil heating and temperature control, main and auxiliary diesel engine temperature control, evaporator operation, etc. Marine steam generation plant is a complex system, demanding in terms of control. The paper describes basic parts, operation and control principles of the ship's steam generator based on the Kongsberg engine room simulator, ERS L11 5L90MC-VLCC, installed at the Faculty of Maritime Studies in Split. It is a diesel-mechanic propulsion plant that is common in merchant ships, and in this case is represents an engine room of a very large crude carrier (VLCC). The control system architecture and its implementation are analyzed. As an example of the possibility of analysing the operation of the system in case of unexpected situations, a simulation of the failure of the boiler steam pressure during the operation of the steam turbines operating the oil pumps was performed. For this case, the response of the water level regulator in the boiler was recorded.