Kajian Stabilitas Kapal Ikan Berbahan Glass Reinforced Plastic (GRP) Dengan Menggunakan Metode Perhitungan Krylov dan Barnhart-Thewlis

Husein, Muhammad Rozzaqi (2026) Kajian Stabilitas Kapal Ikan Berbahan Glass Reinforced Plastic (GRP) Dengan Menggunakan Metode Perhitungan Krylov dan Barnhart-Thewlis. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Stabilitas kapal merupakan aspek penting dalam perancangan dan keselamatan operasional kapal ikan yang mengalami variasi kondisi muatan selama kegiatan penangkapan. Formula empiris Barnhart-Thewlis umum digunakan dalam perhitungan stabilitas awal karena kepraktisannya, namun formula tersebut disusun berdasarkan asumsi dan karakteristik kapal kargo standar sehingga penerapannya pada kapal ikan berbahan Glass Reinforced Plastic (GRP) berpotensi menghasilkan deviasi terhadap hasil perhitungan dengan metode Krylov. Penelitian ini bertujuan untuk mengevaluasi tingkat akurasi formula Barnhart-Thewlis serta mengembangkan modifikasi formula yang lebih sesuai untuk kapal ikan GRP. Metodologi dilakukan dalam empat tahap, yaitu pemodelan lambung 20 kapal ikan GRP menggunakan Maxsurf Stability, perhitungan kurva GZ melalui pendekatan Krylov sebagai referensi, evaluasi akurasi formula Barnhart-Thewlis melalui metrik normalized Root Mean Square Error (nRMSE), serta modifikasi koefisien melalui regresi Ordinary Least Squares (OLS) dengan penambahan dua suku koreksi geometri lambung. Hasil evaluasi menunjukkan bahwa formula Barnhart-Thewlis menghasilkan rata-rata nRMSE sebesar 119,8% sehingga jauh melampaui ambang batas keberterimaan 30%. Formula modifikasi yang diperoleh dari hasil regresi (α = 0,334; β = −0,004; γ = −0,077; ε = −0,244; δ₁ = +0,164; δ₂ = −0,037) berhasil menurunkan rata-rata nRMSE menjadi 24,1% dengan tingkat reduksi sebesar 79,9% dan 19 dari 20 kapal (95%) memenuhi kriteria keberterimaan. Formula hasil modifikasi terbukti memiliki kinerja prediksi yang lebih baik dan dapat digunakan sebagai alat estimasi stabilitas awal pada tahap desain konsep kapal ikan berbahan GRP.
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Ship stability is a critical aspect of the design and operational safety of fishing vessels, which experience varying load conditions during fishing activities. The Barnhart-Thewlis empirical formula is commonly used in initial stability calculations because of its practicality. However, the formula was developed based on the assumptions and characteristics of standard cargo vessels, making its application to Glass Reinforced Plastic (GRP) fishing vessels prone to deviations from actual hydrostatic calculation results. This study aims to evaluate the accuracy of the original Barnhart-Thewlis formula and develop a modified formula that is better suited for GRP fishing vessels. The methodology consisted of four stages: hull modeling of 20 GRP fishing vessels using Maxsurf Stability, GZ curve calculation through the Krylov approach as a reference, accuracy evaluation of the original Barnhart-Thewlis formula using the normalized Root Mean Square Error (nRMSE) metric, and coefficient modification through Ordinary Least Squares (OLS) regression with the addition of two hull-geometry correction terms. The evaluation results show that the original Barnhart-Thewlis formula produced an average nRMSE of 119.8%, far exceeding the 30% acceptance threshold. The modified formula obtained through regression (α = 0.334; β = −0.004; γ = −0.077; ε = −0.244; δ₁ = +0.164; δ₂ = −0.037) successfully reduced the average nRMSE to 24.1%, representing a reduction of 79.9%, with 19 out of 20 vessels (95%) meeting the acceptance criterion. The modified formula demonstrates significantly improved prediction performance and can be used as a more reliable empirical approach for the preliminary stability assessment of GRP fishing vessels.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Stabilitas Kapal, Kapal Ikan GRP, Barnhart-Thewlis, Regresi OLS, nRMSE, Ship Stability, GRP Fishing Vessel, Barnhart-Thewlis, OLS Regression, nRMSE
Subjects:	H Social Sciences > HA Statistics > HA31.7 Estimation V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering V Naval Science > VM431 Fishing boats V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM761 Stability of ships
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User:	Muhammad Rozzaqi Husein
Date Deposited:	01 Aug 2026 03:15
Last Modified:	01 Aug 2026 03:15
URI:	http://repository.its.ac.id/id/eprint/137598

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