Alignment deviations remain one of the main causes of excessive vibration amplitudes among all rotating equipment. Their influence is particularly noticeable in ship shaft lines since their length is often much greater than their diameter. Dial gauges and laser measuring instruments are the most commonly used methods for measuring the alignment deviations of ship shaft lines. Due to the increasingly common use of vibration diagnostics in shipbuilding, it is necessary to develop methods to identify shaft misalignment using vibration methods. The authors of this study identified the spectra components corresponding to the misalignment of a working test station of a ship’s shaft line. Identification was carried out in two stages: based on an analysis of the FEM model using the Abaqus program and based on measurements on a unique laboratory stand. The obtained results confirm the possibility of using FEM simulations in the operational diagnosis of shaft line alignment deviations.

This paper presents the computational tool designed to calculate and optimize the performance characteristics of marine propellers, specifically Wageningen B-series propellers. The tool consists of two main modules: the thrust calculator, which estimates the thrust and efficiency of a propeller based on empirical and experimental data, and the optimization module, which utilizes brute-force and genetic algorithm methods to determine the optimal propeller configurations. By integrating basic input parameters such as ship speed, propeller diameter, pitch, and other essential characteristics, the tool is implemented to search for and find the solution for improving propulsion efficiency. The effectiveness of the tool is demonstrated through case studies on two vessels, a container ship and a special-purpose vessel, where significant improvements in propeller performance were identified. The tool as described in this paper represents a straight forward method for propulsion performance optimization in practical maritime operations.

The organization of maintenance means the organization of the workforce (with tools and knowledge) required for maintenance and the provision of the consumables and spare parts required for this maintenance. Therefore, the organization of maintenance is a complex process where it is necessary to use modern tools such as Computerized Maintenance Management Systems to make it as simple and successful as possible. Many industries have developed special systems that meet their specific requirements and needs. The maritime industry has its own peculiarities and differs in its rules and regulations from the land-based industry, and it is to be expected that the Computerized Maintenance Management Systems intended for it will differ from the systems used in the land-based industry. In order to determine the differences between the design of the system in the maritime and land-based industries, four different systems were analyzed in this paper, two for the maritime industry and two for the land-based industry. As no significant conceptual differences were found between the systems, the actual use of the system was analyzed to determine what should be done in the maritime industry within Computerized Maintenance Management Systems to comply with rules and regulations.