Seakeeping of semi-swath using fin stabilizer with fuzzy logic controller in following seas

Abstract

Semi-SWATH ship design has a low restoring force at bow that causes a tendency to bow-dive when running in following seas. In some conditions, the foredeck found to be immersed under the rear-wave when the ship running from the wave-crest to the wave-trough. The ship is having acceleration, and the momentum force is increases push the ship to dive. The condition may cause the ship has lost of control even the crew on the deck can feel thrown forward. In this research, fin stabilizer was applied to reduce the effect of those conditions with application of fuzzy logic controller. The controller calculates the angle for the fin stabilizer based on the pitch angle. The fin at both ends of the ship’s hull increase the lift force, reduce the trim angle, and restrain the ship from dynamic high acceleration. A numeric time-domain program developed to analyze the ship seakeeping in high wave of following sea. The results showed the controller of fin stabilizer has a significant effect in preventing the ship from the unsafe condition.