Penjadwalan dalam proses reparasi sering kali tidak sesuai dengan perencanaan awal di main schedule dari kapal tersebut. Keterlambatan dari suatu proyek pengerjaan bangunan kapal baru atau reparasi kapal akan menimbulkan kerugian yang berdampak kepada banyak pihak; baik pihak galangan, owner, dan pihak ketiga. Salah satu cara yang efektif untuk meminimalisir terjadinya keterlambatan adalah melakukan percepatan dengan Critical Path Method (CPM). Objek penelitian yang dipilih adalah reparasi kapal TB. Patra Tunda 3001. Tujuan penelitian ini adalah mendapatkan durasi baru setelah dilakukan reschedule reparasi kapal, menemukan aktivitas pekerjaan pada lintasan kritis, mendapatkan nilai produktivitas tenaga kerja, mencari waktu dan biaya paling optimal untuk mempercepat durasi proyek dengan adanya crashing melalui opsi perbandingan dua alternatif yaitu penambahan jam kerja (jam lembur) dan penambahan tenaga kerja. Total biaya normal sebesar Rp 9.360.000. Dari analisa pengolahan data didapatkan kesimpulan bahwa penambahan jam kerja (jam lembur) dan penambahan tenaga kerja menunjukkan percepatan yang sama optimalnya dengan hasil 25% yaitu 4 hari lebih awal dari total durasi nomal proyek 16 hari. Terdapat selisih biaya 39,31% lebih besar dari durasi normal dengan alternatif penambahan jam kerja (jam lembur) dan selisih pengurangan biaya 27,35% lebih kecil dari durasi normal dengan alternatif penambahan tenaga kerja. Reschedule Repari Kapal TB. Patra Tunda 3001 dengan penambahan kerja lebih efisien dan optimal pengerjaannya.

A planing hull is a high-speed craft with relatively complex hydrodynamic characteristics. An increase in speed can induce a significant change in trim angle with an increment in ship drag. One solution to reduce ship resistance is to use an interceptor. This research aimed to analyze the hydrodynamics of a planing hull vessel by applying an interceptor. The fundamental aspects reviewed included the analysis of drag, trim, heave, and lift force. The interceptor would be investigated on the basis of its integrated position at its height. This research also used the computational fluid dynamic (CFD) method in calm water conditions. All simulations were conducted with the same mesh structure, which allowed the performance evaluation of the interceptor in calculating turbulent air–water flow around the ship. Numerical calculations used the Reynolds-averaged Navier–Stokes (RANS) equation with the k–ε turbulence model to predict the turbulent flow. The vertical motion of the ship was modeled using dynamic fluid–body interaction (DFBI) in the fluid domain through an overset mesh technique. The numerical approach was compared with the experimental test results of Park et al. to ensure the accuracy of the test results. The interceptor was designed at the transition phase, which showed the highest trim angle followed by high drag. The interceptor would experience negative trim at high speeds; thus, it was not recommended. The research results indicated that the most effective use of the interceptor was at Froude number 0.87 close to the chine position with a height of 100%. This interceptor could reduce a maximum of 57% drag, 17% heave, 8.48% trim, and 0.12% lift force. The interceptor could increase excessive drag and trim at Froude numbers over 1.16. The interceptor proved to be remarkably useful in trim control and ship drag reduction, but selecting the wrong dimensions and positions of the interceptor could endanger the ship. This simulation was performed on Aragon-2; thus, the interceptor performance may possibly change if a different hull geometry is used.

The patrol boat is one of the critical aspects for archipelago countries, such as Indonesia, to supervise and maintain the sea border. Due to rough sea conditions, the patrol boat could lose its stability due to the loss of a self-righting roll moment in severe waves. One of the most challenging aspects is to ensure the sufficient stability of the patrol boat during rough conditions. Another challenge is to design a boat that has a self-righting moment during rolling in extreme conditions. This paper examines the design of an anti-capsize ship by improving the self-righting moment with different deck houses height. The rough condition is described when the boat experiences a roll angle of 170°. The principal dimensions of the patrol boat, i.e., Lpp, B, H, T, are 13.0 m, 4.2 m, 2.19 m, and 1.15 m, respectively. Four different deck house heights are compared to obtain the best self-righting roll moment with a height increment of 0.1 m. The physical model is implemented with ship model 1:27.4. In addition, computational fluid dynamics (CFD) is also used to support the proof of the existence of the self-righting roll moment. It is revealed that the center of gravity and buoyancy are essential parameters to acquire the self-righting moment. The height of the deckhouse improves the center of the metacenter, which influences the righting arm of ship stability. The results show that our ship design has a self-righting moment during heel at 180°.

Single point mooring of Conventional Buoy Mooring (CBM) is an offshore mooring structure where the mooring line attached from bow of ship to CBM. Lack buoyancy on CBM needed Additional subsea floaters to increase buoyancy of CBM. Time domain simulation on Moses software version 11 used to calculate the effect of the variation number of subsea floaters to chain tension and CBM Motion. The result is a single configuration subsea floater has higher tension and extreme motion than multiple configuration subsea floaters.

⎯ ASTM A36 steel is a steel commonly used in shipbuilding construction. The property of steel that is highly avoided is susceptible to corrosion or corrosive which can reduce the strength of the structure. Over time, technology has developed, and methods have been found to inhibit the rapid rate of corrosion, coating process is one of them. The success rate of coating process is also strongly influenced by the surface preparation process. The surface preparation process in this study was by differentiating the size variations of the SG18, SG25, and SG40 steel grit abrasive materials and the spraying pressure of the 5 bar, 6 bar, and 7 bar abrasive materials and the provision of scratch defects on the specimens that had been coated with epoxy primer paint. The purpose of the research conducted was to analyze variations in size of the abrasive material, the spraying pressure of the abrasive material, and which combination of variations is the best for specimens considered to have been scratched. In each variation, the value of the corrosion rate will be increased when the size of the material increased and the value of the corrosion rate increases when the spraying pressure decreases. The results obtained from this study indicate that the lowest corrosion rate value is 0.0027 mmpy with the outstanding category of the variation used, which is grit SG40 steel abrasive material and at a pressure of 7 bar.