The internet of ships(IoS) serves as the carrier for maritime information exchange. Based on the blockchain technology, this paper aims to establish a reliable information exchange mechanism on the IoS by using a credibility calculation method for navigation events in the IoS and a reputation management scheme for the ships involved. This scheme draws on the principles of information filtering to obtain the comprehensive similarity of ships, calculates the fused rating through reverse computation of weighted entropy, and then updates the reputation value of responding ships based on the deviation between their rating and the fused rating. Afterwards, the paper establishes a fitting relationship between the reciprocal of reputation value and rating error using the least squares method, so that the reputation value of the reporting ship is computed and updated. In addition, a delegated proof of stake(DPoS) consensus mechanism is developed, which depends on the reputation values of ships. This mechanism prioritizes the selection of ships with higher reputation values as witness ships to maintain the stability and efficiency of the system's blocking environment. Empirical results demonstrate the effectiveness of the proposed scheme, showing that under conditions of 40% ship misuse, the accuracy of authenticating navigational events remains above 75%. The study confirms that the proposed scheme not only improves the accuracy of authenticity determination, but also skillfully identifies and restricts the activities of malicious vessels. This helps to strengthen the security and stability of the IoS environment.