Modern diesel propulsion system, which is nowadays being used on board the majority of merchant ships, represents an exceptionally complex ship’s machinery system, consisting of a number of interconnected and interdependent subsystems, directly affecting reliability and safety of the ship in general. Therefore, a high performance and a high level of availability of all propulsion systems is required. A prominent role in the global merchant fleet is played by the propulsion based on the two-stroke low-speed reversing diesel engine and on the fixed propeller as a dominant propulsor. Due to the electrical energy primary production system failure or to the diesel generators failure, followed by the switchover to the emergency supply of electrical energy, the ship runs out of propulsion, which cannot be restored in spite of the proper functioning of the main engine. Out of the analysis of relevant global databases on ship’s machinery failures, it is obvious that the most frequent failures occur precisely on the generator-running diesel engines. Therefore, it is necessary to define a propulsion restoration model which would not depend on the primary electrical energy, thus increasing considerably the ship’s propulsion safety. A research carried out on intelligent ship’s machinery development projects has pointed out a possibility of setting up a propulsion restoring model by using the intelligent engine hydraulics and by introducing hydro generators into the system. Further possibilities have been also analyzed, from the increase of the emergency generator power, over the additional capacity of the accumulator units to the installation of pumps attached to low-speed reversing propulsion engine. Following a thorough analysis, a reliable drive model has prevailed, based on the use of a shaft generator and an excitation engine, thus enabling the propulsion restoring subsequent to a total failure of the electrical energy primary production system, and to the self-propelled ship navigation. As a result of, a model of the ship’s auxiliary system has been defined in terms of the ship’s propulsion safety.