This article examines the selection methodology of class surveys of a shipborne engine room and its impact on
the reliability and operation indicators of a marine power plant. We describe the characteristics of four available
class survey methods and then carry out a reliability analysis on the basis of four months of activity on
six different ships operating on international voyages, taking into account the two most common supervision
methods: renewal and continuous survey. Based on this analyses, we conclude that the reliability indices of
a marine power plant, classified according to the continuous method, were slightly lower than for the renewal
method. However, we identified potential benefits in terms of overall ship maintenance costs, due to a faster and
more economical 5-yearly shipyard survey.