Pengendalian Persediaan Material Baja Pada Perusahaan Galangan Perbaikan Kapal Menggunakan Metode Continuous Review

Adhastyananda, Ida Bagus Riscy (2025) Pengendalian Persediaan Material Baja Pada Perusahaan Galangan Perbaikan Kapal Menggunakan Metode Continuous Review. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Sebuah perusahaan galangan kapal di Balikpapan melayani perbaikan berbagai jenis kapal dari berbagai class. Selain kualitas, ketepatan waktu merupakan salah satu competitive advantage di industri perbaikan kapal. Lingkup kerja di industri ini sebagian besar diketahui setelah adanya inspeksi di atas dock. Hal ini menyebabkan ketidakpastian akan kebutuhan material. Persediaan yang tidak direncanakan dengan baik akan meningkatkan risiko keterlambatan akibat kekurangan material. Kegiatan replating merupakan salah satu proses perbaikan yang paling sering dilakukan disana, material baja adalah direct material untuk proses tersebut. Proses manajemen persediaan untuk material tersebut belum optimal. Pada penelitian kali ini dilakukan proses perbaikan terhadap kebijakan eksisting. Tahap awal yang akan dilakukan adalah klasifikasi ABC berdasarkan data permintaan material baja, hanya material kategori A yang masuk tahap selanjutnya karena memiliki proporsi nilai persediaan yang paling besar. Tahap berikutnya adalah forecasting berdasarkan data historis permintaan material kategori A tersebut. Metode forecasting yang digunakan adalah exponential smoothing dan long short-term memory (LSTM). Metode forecasting dengan nilai eror terendah yaitu LSTM, permintaan bulanan dan tahunan yang dihasilkannya akan digunakan untuk perhitungan sistem continuous review model Q backorder. Metode tersebut akan menjadi kebijakan perbaikan dengan menghasilkan quantity order, safety stock, dan reorder point pada masing-masing material. Simulasi dlikakukan pada kebijakan perbaikan dan kebijakan eksisting, kemudian dilakukan perbandingan antara kedua kebijakan tersebut. Kebijakan perbaikan dapat menghemat biaya sebesar Rp2.671.910.250,20 atau 7,645% lebih rendah dari kebijakan eksisting.
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A shipyard company in Balikpapan provides repair services for various types of vessels across different classification societies. In addition to quality, timeliness is a key competitive advantage in the ship repair industry. The scope of repair work is largely identified only after dock inspection, which creates uncertainty in material requirements. Poorly planned inventory management increases the risk of delays due to material shortages. Replating is one of the most frequently performed repair activities at the shipyard, and steel materials serve as direct materials for this process. However, the inventory management of these materials has not yet been optimal. This study proposes improvements to the existing inventory policy. The initial stage involves ABC classification based on historical steel material demand data. Only Category A materials are selected for further analysis, as they represent the largest proportion of inventory value. The next stage involves forecasting the demand for Category A materials using historical data. The forecasting methods applied are exponential smoothing and Long Short-Term Memory (LSTM). Among the methods evaluated, LSTM yields the lowest forecasting error; therefore, the resulting monthly and annual demand forecasts are used as inputs for the continuous review (Q) backorder inventory model. The proposed method serves as an improved inventory policy by determining the optimal order quantity, safety stock, and reorder point for each material. A simulation is conducted to compare the proposed policy with the existing policy. The results show that the proposed inventory policy reduces total inventory costs by IDR 2,671,910,250.20, which is 7.645% lower than the existing policy.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Forecasting, Ship Repair, Inventory Management, ABC Classification, LSTM, Continuous Review
Subjects:	H Social Sciences > HD Industries. Land use. Labor > HD55 Inventory control
Divisions:	Interdisciplinary School of Management and Technology (SIMT) > 61101-Master of Technology Management (MMT)
Depositing User:	Ida Bagus Riscy Adhastyananda
Date Deposited:	21 Jan 2026 00:54
Last Modified:	21 Jan 2026 00:54
URI:	http://repository.its.ac.id/id/eprint/129875

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