Resistance Analysis of Three Identical Trimaran Hulls with Separation to Length Ratio Variations

A ship produces wave-making resistance that can increase the total resistance of the ship. This disadvantage is applied to a trimaran vessel with a main hull identical in size and shape, but with a side hull having a different space-to-length ratio (S/L) to determine the interference drag generated compared to three hulls that move without interfering with each other. The model for this study is based on identically sized NPL 4a hulls. This analysis was conducted using the CFD method, with validation using the NPL 4a monohull model subjected to a towing test using the ITTC standard towing tank. Interference resistance analysis was conducted by comparing the total resistance generated by three identical monohulls with a trimaran that uses three identical hulls on the main hull and side hull with S/L ratio, S/L = 0.2; S/L = 0.3; and S/L = 0.4 and has Froude numbers (Fr) at: 0.2, 0.4, and 0.6. With the final result, the hull with a S/L ratio 0.2 has a significantly higher total resistance coefficient. The highest and lowest wave elevations are at the trimaran hull with a S/L ratio of 0.2 and the model trimaran with the ratio of S/L 0.2 has the highest interference total resistance coefficient in each Froude number.