Fishing vessels with a length $\left({\mathrm{L}}_{\mathrm{BP}}\right)$ of less than 100 m are generally not required to comply with the mandatory IMO Ship Maneuverability Standards. Therefore, an analytical method using empirical formula is preferred rather than a model test, which consumes a lot of time and monetary resources in estimating the maneuverability at the design stage. However, most empirical formulas have been derived from the model test results of merchant ships, and in the process, estimation errors may occur when hull-form parameters ($\mathrm{L}/\mathrm{B}$ or ${\mathrm{C}}_{\mathrm{b}}\mathrm{B}/\mathrm{L}$) with high correlation are applied to fishing vessel hull form whose characteristics are different from those of merchant ships. Therefore, a modified empirical formula was derived from previous research by including major parameters of fishing vessel hull form in the Kijima 90 empirical formula. In this study, maneuverability of stern trawler hull form is estimated for validating a modified empirical formula. The study confirmed that including characteristic parameters of the fishing vessel hull form in the empirical formula developed for merchant ships could improve the accuracy of estimation.

The length between perpendiculars (LBP) of most fishing vessels is less than 100 m. Thus, they are not subject to the International Maritime Organization (IMO) maneuverability standards, affecting research on maneuverability. However, upon referencing the statistics of marine accidents related to vessel maneuvering, the number of marine accidents caused by fishing vessels is 3 to 5 times higher than that of merchant ships. Therefore, systematic and consistent research on the maneuverability characteristics of fishing vessels is surely required. In particular, a fishing vessel frequently enters and departs from the same port and often sails at high speed due to familiarity with the characteristics of the situation, which may cause maneuvering-related accidents. In this study, the maneuverability of a fishing vessel in shallow water was predicted using an empirical formula. The results of this study are expected to not only be of great help in conducting simulations when analyzing marine accidents involving fishing vessels, but will also provide unique parameters of fishing vessels that lead to developing autonomous vessels.

To accurately estimate the navigation safety of a barge in still water and waves, computational fluid dynamics (CFD) was used to calculate the hydrodynamic force on the barge and simulate the flow field to comprehensively study the effect of skeg for wave drift force and directional stability of the barge. With respect to the wave drift force, the steady surge force and steady sway force are found to decrease due to the skeg effect in both short and long wavelength regions. The overall steady yaw moment tends to be reduced by the skeg. As the drift angle increased, the sway force and yaw moment also increased. The changing trend in the sway force varied with the angular velocity, depending on the installation of the skeg, and it was noted that the yaw moment value significantly increased because of the skeg. Owing to the effect of the skeg installed on the barge, the yaw damping lever became larger, while the sway damping lever became smaller regardless of waves. It was confirmed that the directional stability was improved both in still water and head waves.

Most fishing vessels are less than 100 m in length between the perpendiculars, for which adherence to the International Maritime Organization maneuverability standards are not mandatory. In the design stage of fishing vessels, maneuverability is estimated using empirical formulas—mainly analytical methods—rather than costly and time-consuming model tests. However, the empirical formula is developed through the process of regression analysis on the model test results from merchant ships’ hull form and applying the same to the fishing vessels’ hull form may result in an estimation error due to the differences in the vessels’ characteristics—e.g., $\mathrm{L}/\mathrm{B}$, $\mathrm{B}/\mathrm{d}$ and ${\mathrm{C}}_{\mathrm{b}}·\mathrm{B}/\mathrm{L}$—. In a previous study, the authors of this paper derived a modified empirical formula by adding the hull form parameters of trawl fishing vessels to the existing empirical formula based on those of merchant ships. This study analyzes the validity of the modified empirical formula in depth by applying it to a newly-built training vessel that has the hull form of a trawl fishing vessel. As a result of the study, the estimation results were improved by including the parameters of the hull form of trawl fishing vessels in the empirical formula developed for merchant ships.

Among the waste heat discharged from diesel engine, the temperature of the jacket cooling water whose temperature of the heat source is relatively low rises to 85°C. Organic Rankine Cycle(ORC) can effectively recover the low temperature heat source such as jacket cooling water due to its distinctive thermodynamic performance. Therefore, in this study, ORC system for recovering waste heat of jacket cooling water which is a low temperature heat source is constituted. by selecting R245fa and R1234yf as working fluids for low temperature heat sources, the efficiency of the ORC system for the two working fluids is compared. Also, the effect of the saturation temperature change of the evaporator on the system performance is investigated. From the simulation results, it is found that the efficiency of R2345fa is 26∼35% higher than that of R1234yf. When the saturation temperature of evaporator is 353 K, the efficiency of ORC system using R245fa as the working fluid increases by 11%.