EN
mportance of reliability and safety in the operation phase of engine rooms has been proven. A concept of designing engine rooms taking into consideration their reliability, safetyof functioning as well as ecological features has been proposed. The need for as well as themain principles of carrying out empirical research in particular ship design stages have been introduced. Possibilities of the use of the semi-Markov theory in designing enginerooms have been justified. Possibilities of formulation and importance of hypothesis inscientific research related to engine rooms of sea going and inland ships depending on their particular specific features have been introduced. Examples of such hypothesis and their verification methods have been given. Possibilities of the use of semi-Markov processes in optimization of the ship operation have been signalled