The statistical analysis of existing data of similar ships is an effective tool for an initial estimation of principal parameters of a ship to be designed. High values of the correlation coefficient could signify that a high level of geometric and weight similarity occurs. If this statement is proved and supported by other premises, it means that there is a possibility to create statistical relations allowing to estimate the parameters of ship being designed with a high level of accuracy. This paper presents such case concerning membrane LNG tankers. The resulting parametric relations could be used for the creation of coherent design variants useful for the process of multicriterial optimization of these ships

The global LNG shipping capacity is growing sharply and the number of ordered LNG carriers is very high at the moment. It is possible that Poland will appear among experienced builders of those ships. The author considers the requirements for propul-sion systems of modern LNG carriers, the methods of utilising boil-off gas, different alternatives of power sources. Besides, the paper introduces a preliminary idea of re-search on an optimal solution of propulsion system closely related with the size of the vessel.