Stability and Resistance Analysis of an Asymmetric Catamaran Patrol Boat Design for Natuna Waters

The Natuna Sea, a critical fishery zone for Indonesia, is persistently threatened by Illegal, Unreported, and Unregulated (IUU) fishing activities. Effective maritime law enforcement in this region demands patrol vessels that combine exceptional seakeeping stability with high-speed pursuit capabilities. This study addresses this need by designing and hydrodynamically evaluating a novel 23-meter asymmetric catamaran hull form specifically optimized for patrol missions in Natuna waters. The vessel's intact stability was rigorously assessed according to the IMO Intact Stability Code (A.749(18)) for full and partial load conditions, while its resistance characteristics were analyzed across a speed range of 12 to 40 knots using the Savitsky Planning method. The results demonstrate that the proposed design far exceeds regulatory safety standards, with stability safety margins of 500-800% above IMO minima. The area under the righting lever (GZ) curve (0-30°) was calculated as 21.48 m·deg, significantly higher than the required 3.15 m·deg, indicating robust energy absorption in rough seas. At the maximum operational speed of 40 knots, the total resistance was 110.11 kN, corresponding to a required brake horsepower of 7,224 HP, which can be feasibly delivered by a twin-engine configuration. The design also incorporates a step water deflector, reducing spray resistance by approximately 15%. This study concludes that the asymmetric catamaran configuration presents a technically viable and superior alternative to conventional monohulls, offering an optimal blend of high-speed performance, exceptional stability, and enhanced fuel efficiency for extended patrols in the challenging Natuna Sea environment.