Hydrodynamic improvement of trimarans through multiple foils for trim control, resistance reduction, and wake attenuation in planing operations

Minimizing fuel consumption has become a critical focus in marine vessel development to significantly lower environmental impact and operational costs. One promising approach involves minimizing vessel resistance by installing four hydrofoils—two parallel at the bow and two at the stern—on a trimaran hull. This study assesses the hydrodynamic performance of these hydrofoils across Froude numbers ranging from 1 to 1.5, utilizing Computational Fluid Dynamics with Star-CCM+ (Simulation of Turbulent flow in Arbitrary Regions–Computational Continuum Mechanics (C++ based)) software and k-epsilon turbulence model. Mesh sensitivity analysis was conducted, and numerical results were validated against the experimental data of DC372 catamaran and Wigley trimaran, showing good agreement. Findings reveal that trim (height difference between bow and stern) behavior of trimaran varies based on foil type and Froude number. Among tested vessels, asymmetric foiled trimaran demonstrates the lowest trim, while symmetric foiled produces the highest. The non-hydrofoil trimaran shows stable trim up to a Froude number of 1.3, beyond which it increases notably. In terms of sinkage (downward displacement of a vessel), asymmetric hydrofoil causes the most significant sinkage, while non-hydrofoil trimaran exhibits the least. Asymmetric hydrofoil achieves the highest lift-to-drag coefficient ratio across all Froude numbers, offering superior efficiency, while symmetric hydrofoil maintains consistent performance at various speeds. Overall, the asymmetric foil stands out for its reduced trim, sinkage, and drag, making it an excellent choice for improving trimaran efficiency and stability. Meanwhile, symmetric hydrofoils help attenuate the wake around and behind the vessel at most Froude numbers, offering additional benefits for certain operational conditions.