The article deals with the issue of fire prevention at the stages of construction, utilization and repair and recovery operations on large-capacity surface and submarine vessels. A fire prevention methodology based on an adaptive early fire detection system and a prediction system was developed. The algorithm of the fire prevention system operation was given, which includes 15 stages. The fire prevention methodology is based on a model for monitoring and forecasting on the basis of the first and second level classifiers, which solve the problems of determining the level of fire danger of the technological processes performed, the level of influence of the characteristics of fire load on the ship, the characteristics of the external environment, taking into account the influence of the current time, day of the week and month. This model on the basis of input parameters of the object of construction, utilization or reconstruction determines the level of influence of these characteristics on the level of fire danger of the whole object. Based on the study, 8 main first level classifiers influencing the level of fire danger of the object were identified. The complexity of this methodology is that the object of construction, utilization and reconstruction is a dynamically changing system with an inconstant set of input parameters and constantly changing geometric dimensions. This methodology takes into account all changes and a set of input parameters at the beginning of the working day and gives the resulting value of the fire danger level at each unit of time.