This paper presents the results of previously carried out analyses regarding efficiency and criteria evaluation of various propulsion plants of modern LNG (Liquid Natural Gas) carriers. The results of previous identification and quality assessment of waste heat energy sources of a CST (Conventional Steam Turbine) plant are presente. In this paper the possibility of use a steam jet injector in order to recover the latent heat is analysed. Calculations were carried out for an injector equipped with a de Laval nozzle, determining the thermodynamic state parameters of the mixture of drive steam and sucked in steam as well as the steam on the outlet of the injector for the various ejection ratios. On the basis of the results of the injector calculation, the heat balance of a simple regenerative Clausius – Rankine steam cycle (with one regenerative heater – deaerator) was carried out. The degree of regeneration (increase of the thermal efficiency) for cycle using the regenerative injector was determined. Based on results the further research directions for complex plants using a steam jets are indicated.