ANALISIS PERFORMANCE HULL VANE NACA 4418 PADA KAPAL PATROLI 14,1 M DENGAN VARIASI SUDUT SERANG 5° DAN 10° MENGGUNAKAN COMPUTATIONAL FLUID DYNAMICS

Abstract

Patrol boats are a strategic national asset for archipelagic countries such as Indonesia, playing a vital role in enforcing maritime sovereignty and securing vast territorial waters. Their operational effectiveness relies on high-speed cruising, superior maneuverability, and optimal fuel economy, as they frequently undertake prolonged sea missions. This study investigates the impact of the NACA 4418 hydrofoil (Hull Vane) attack angle on the total resistance of a 14.1‑meter patrol boat cruising at 25 knots, corresponding to a Froude number of approximately 0.65. Three‑dimensional numerical simulations were executed using ANSYS Fluent 2020 R2 with a pressure‑based, steady‑state, single‑phase solver and the k‑ω SST turbulence model, examining attack angles of 5° and 10°. The simulations were performed on a 1:5 scaled model (waterline length of 2.4 m), adhering to standard towing tank testing protocols. Model validation against the Holtrop‑Mennen empirical method for the bare hull showed a deviation below 3%. The findings reveal that the 5° angle reduces model resistance by 7.8% (dropping from 134.59 N to 124.16 N) with a peak pressure of 7,566 Pa, whereas the 10° angle achieves only a 3.5% reduction while exhibiting higher pressure (8,125 Pa). Visualization of streamlines and pressure contours identifies significant flow separation on the suction side at 10°, which degrades performance. Notably, propulsion efficiency improves by 5.1% at the optimal 5° configuration. Consequently, the NACA 4418 at a 5° attack angle delivers the most effective resistance reduction among the tested variants for small high‑speed patrol vessels. This research offers preliminary quantitative evidence and practical design guidance for retrofitting existing patrol boats operating in Indonesian waters.