Numerical Investigation of Trim and Sinkage Effect on Resistance of a Semi-planing Monohull

Trim and sinkage of a ship have a significant impact on its resistance, particularly in the case of semi-planing vessels, where the degree of trim and sinkage can vary considerably depending on the ship's speed. In this study, a computational fluid dynamics analysis was carried out to investigate trim and sinkage effect on a semi-planing monohull ship model at six different speeds, with Froude numbers (Fr) ranging from 0.2 to 0.7. The study investigates a ship model resistance with completely no trim and sinkage (fixed condition) and a ship with natural motion with trim and sinkage (free condition). The findings show that a total resistance of free condition is higher than the fixed condition, with the largest difference being 68.4% occurring at Fr 0.6. From the investigation shows that the dominant factor influencing the resistance is the residuary resistance, while the friction resistance is not significantly affected by trim and sinkage conditions.