The topic of the study is the issue of assessing the safety of the use of autonomous type vessels and suitable criteria for the mode of operation, which has a priority status, since currently a large number of prototypes of such vessels are planned to be launched. It is noted that classification societies determine the rules of classification and construction of this type of vessels. Using the method of analyzing the types and consequences of failures, which is well-established in the aerospace industry in the second half of the last century, is suggested in the paper. For this purpose, the concept of risk priority taken from the analysis of the ratings of the failures occurrence and consequences is used. All parameters for determining the priority of risk are obtained during the analysis of accidents of the various types of vessels, including those, which are without crew. The rating of the failure mode occurrence in autonomous navigation, the rating of the failure mode critical consequences and the failure mode detection rating for autonomous vessels are considered. Each of these types of rating includes ten levels. The assessment of failure levels consists of four stages. Initially, it is necessary to identify potential failure modes. Then the parameters of the risk priority concept and the type of failure are evaluated. For each operational mode of operation, namely manual control, remote or autonomous control, the risk priority concept scenario is calculated. The analysis of the calculation results is carried out and proposals are formulated and recommendations of corrective actions are given. The results obtained have shown that under the same conditions, the range of the risk level varies depending on the operating modes of an autonomous vessel. The results are presented in the table of the choice of corrective actions and given graphically for visual assessment and direction of danger. The proposed approach makes it possible to choose the most safe mode of operation for this level of risk, as well as to predict the necessary corrective actions.