The authors have investigated the distribution of organotin and its alternatives in sediment in various parts of Japan. The concentration of organotin compounds extracted from samples was the highest in Tanabe Bay, followed by Osaka Port, Otsuchi Bay and Maizuru Bay. Especially, Tanabe Bay had a high concentration of triphenyltin. Concerning the alternative biocides, Diuron concentrations were higher at international trading ports and higher concentrations of Irgarol 1051 were observed at fishing ports. Furthermore, the concentrations of tributyltin (TBT), TPT and Irgarol 1051 were high near pollution sources, whereas Diuron was distributed widely away from pollution sources and Sea Nine 211 was detected less frequently. In Southeast Asia, the distribution of antifouling biocides was similar to that of the coastal areas in Japan. Organotin compounds and their alternative biocides were also detected in deep sea sediment.

IMO adopted a revision of MARPOL Annex VI to establish the Energy Efficiency Design Index (EEDI) for new build vessels in July 2011. Evaluation of Energy Efficiency Existing Ship Index (EEXI) just after drydock and annual evaluation of Carbon Intensity Indicator (CII) rating have been also in force by revision of same treaty in January 2023. Performance of new build vessel and repair vessel evaluated more precisely and need to satisfy the levels defined in the clause of treaty. Surface roughness of antifouling paints affect significantly for ship performance especially for old vessels. To prevent the performance deterioration by attaching the marine organisms (fouling), proper use of antifouling paint is very important. Revised AFS treaty for restriction of biocide cybutryne have also been came into force in 2023. This is first alternative biocide which is restricted after tributyltin compounds. In this article recent new antifouling paints technologies and utilization of information technologies for practical use of antifouling technology which are developed to cope with recent international treaties are introduced.

The attitude stability of a floating body in response to disturbances, such as waves, is of significant importance for maritime activities especially when transporting personnel. There have been several developments for motion reduction/control, yet existing technologies are not readily applicable to floating bodies like small boats. Moreover, these technologies cannot reduce high-frequency motion or heaving. In this research, the authors proposed stabilizing mechanisms to reduce the 6-DOF motion of a floating body, and conducted fundamental theoretical and experimental studies, which proved motion reduction effects of the proposed auxiliary float devices and propeller units.

When beginners engage in practical training to learn about marine engines, they see many devices and operations for the first time. For this reason, such training requires support from teaching materials that can improve safety and learning efficiency and provide a variety of training options. The purpose of this study is to improve the method to extend the simulation functions to cover a four-stroke diesel engine installed on land, and to verify the effectiveness of the teaching materials. The authors reconstructed the system structure using Python and examined the implementation of the functions related to fuel transfer. It was suggested that the practical training using an actual equipment-based engine simulator can improve trainees' understanding about the entire plant, including piping, more effectively than classroom teaching. In particular, giving beginners simulated experience of devices and equipment thought on-site work as a way to encourage self-study will help them increase motivation for learning.