Hydrodynamic performance comparison of planing catamarans with mono-hulls using numerical and experimental methods

This study addresses the hydrodynamic performance of high-speed planing catamarans compared to equivalent mono-hulls using numerical simulations and experimental validation. The study includes computational fluid dynamics (CFD) simulations to analyse the hydrodynamic behaviour of the catamarans under various operating conditions, such as different speeds, deadrise angles, and static trim angles. Comparison of the numerical simulation results with model tests reveals that the numerical results for the resistance of planing catamarans at high speeds deviate significantly from the experimental data due to strong spray. This discrepancy is systematic (rather than random) and has been recognised and modified. The modified numerical results are sufficiently accurate for further pursuit. Generally, the resistance of a planing catamaran compared to an equivalent planing mono-hull is significantly larger, approximately 25–60 %, while the absolute sinkage is lower. A positive feature of the catamaran is its ability to prevent porpoising instability, especially in boats with a small deadrise angle. Choosing a planing catamaran over a mono-hull must offer other substantial advantages, such as better seakeeping performance, which compensate the higher resistance.