Pengaruh Posisi LCG Terhadap Sudut Trim dan Hambatan Kapal Cepat menggunakan Metode Eksperimental dan Numerik

wijaya, Pandu (2026) Pengaruh Posisi LCG Terhadap Sudut Trim dan Hambatan Kapal Cepat menggunakan Metode Eksperimental dan Numerik. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Performa hidrodinamika kapal cepat tipe planing hull sangat dipengaruhi oleh posisi Longitudinal Center of Gravity (LCG) karena perubahan distribusi massa dapat memengaruhi keseimbangan longitudinal, sudut trim, luas permukaan basah, dan hambatan total kapal. Penempatan LCG yang terlalu jauh ke arah buritan dapat meningkatkan sudut trim, sedangkan penempatan yang terlalu jauh ke arah haluan dapat memperbesar pembenaman haluan dan hambatan gesek. Penelitian ini bertujuan menganalisis pengaruh variasi posisi LCG terhadap sudut trim dan hambatan total kapal planing hull sepanjang 11 meter serta menentukan posisi LCG yang menghasilkan performa hidrodinamika paling optimal. Penelitian menggunakan metode eksperimental melalui pengujian towing tank dan metode numerik Computational Fluid Dynamics (CFD). Simulasi menggunakan model kapal berskala 1:10, model multifase Volume of Fluid, model turbulensi k–ω Shear Stress Transport. Penelitian menguji tiga posisi LCG, yaitu LCG-2 yang bergeser 4,5% LWL ke arah buritan, LCG-3 sebagai posisi desain, dan LCG-4 yang bergeser 4,5% LWL ke arah haluan, pada rentang bilangan Froude 0,396 sampai 0,594. Hasil validasi menunjukkan galat relatif antara hasil CFD dan eksperimen sebesar 0,22% sampai 4,91%, dengan rata-rata 1,94%. Pergeseran LCG ke arah buritan menghasilkan sudut trim terbesar, yaitu 2,82° sampai 3,30°, sedangkan pergeseran ke arah haluan menghasilkan sudut trim terkecil, yaitu 1,95° sampai 2,30°. Posisi LCG desain menghasilkan sudut trim sebesar 2,36° sampai 2,76° serta hambatan total model paling rendah, yaitu 0,2737 sampai 0,7263. Posisi optimum diperoleh pada LCG-3 yang terletak 0,611 m dari aft perpendicular atau sekitar 55,5% LWL dari AP. Hasil tersebut menunjukkan bahwa posisi LCG desain memberikan keseimbangan terbaik antara sudut trim, distribusi tekanan, luas permukaan basah, dan hambatan total kapal.
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The hydrodynamic performance of a high-speed planing hull is strongly influenced by the position of the Longitudinal Center of Gravity (LCG), as changes in mass distribution may affect longitudinal balance, trim angle, wetted surface area, and the vessel’s total resistance. Placing the LCG too far toward the stern may increase the trim angle, whereas positioning it too far toward the bow may increase bow immersion and frictional resistance. This study aims to analyze the effects of LCG position variations on the trim angle and total resistance of an 11-meter planing hull and to determine the LCG position that provides optimum hydrodynamic performance. The study employed an experimental method through towing tank testing and a numerical method using Computational Fluid Dynamics (CFD). The simulations used a 1:10 scale vessel model, the Volume of Fluid multiphase model, and the k–ω Shear Stress Transport turbulence model. Three LCG positions were investigated, namely LCG-2, which was shifted by 4.5% LWL toward the stern, LCG-3 as the design position, and LCG-4, which was shifted by 4.5% LWL toward the bow, within a Froude number range of 0.396 to 0.594. The validation results showed that the relative errors between the CFD and experimental results ranged from 0.22% to 4.91%, with an average error of 1.94%. Shifting the LCG toward the stern produced the highest trim angles, ranging from 2.82° to 3.30°, whereas shifting it toward the bow produced the lowest trim angles, ranging from 1.95° to 2.30°. The design LCG position produced trim angles ranging from 2.36° to 2.76° and the lowest model-scale total resistance, ranging from 0.2737 to 0.7263. The optimum position was obtained at LCG-3, located 0.611 m from the aft perpendicular, or approximately 55.5% LWL from AP. These results indicate that the design LCG position provides the best balance among trim angle, pressure distribution, wetted surface area, and the vessel’s total resistance.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Computational Fluid Dynamics, hambatan total, Longitudinal Center of Gravity, planing hull, sudut trim, Computational Fluid Dynamics, Longitudinal Center of Gravity, planing hull, total resistance, trim angle.
Subjects:	V Naval Science > V Naval Science (General) V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User:	Pandu Wijaya
Date Deposited:	04 Aug 2026 06:40
Last Modified:	04 Aug 2026 06:40
URI:	http://repository.its.ac.id/id/eprint/143414

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