Performance Prediction of Planing Catamarans Using Mathematical and CFD Models

Traditional planing hulls have been a standard in maritime design, yet recent innovations in modern high-speed craft have introduced alternative hull configurations, including tunnels, hydrofoils, and energy-saving devices such as interceptors. The selection of the appropriate hull type has become a critical consideration in the preliminary design phase. In scenarios where ship owners demand increased deck space without compromising speed, designers may propose planing catamaran hulls, characterized by two (demi) planing monohulls connected by a tunnel. These high-speed catamarans offer large spaces making them optimal for diverse military and transportation applications prioritizing spaciousness. The selection process involves a thorough evaluation based on performance, maneuverability, fuel efficiency, and cost-effectiveness. Given the popularity of both planing monohulls and catamarans in high-speed crafts, this paper investigates mathematical models for predicting the performance of catamaran planing hulls. While the mathematical models draw inspiration from planing monohulls in calm water, they consider the interference location and effects between the two half-bodies in catamaran designs by incorporating separation effect parameters. Specifically, this paper explores the implementation of the 2D+T method for the early-stage hydrodynamic design of catamaran planing hulls by using two methods. The first method employs sectional pressure distributions to calculate three-dimensional forces in calm water, the second utilizes momentum variation along the vessel for calculation of three-dimensional forces. In the final stage, a verification comparison is conducted, investigating unsteady Reynolds-Averaged Navier-Stokes (RANS) computations. The findings contribute to engineering community by providing hydrodynamic tools and results that can be used in conceptualizing the design of a high speed craft.