IJOCE (International Journal of Offshore and Coastal Engineering)
IJOCE, International Journal of Offshore and Coastal Engineering, is an academic journal on the issues related to offshore, coastal and ship science, engineering and technology. Published quarterly in February, May, August, and November.
Articles
92 Documents
<![CDATA[Experimental & Numerical Studies of Vertical Motion Acceleration Analysis in Helideck on a Catamaran Floating Crane ]]>
<![CDATA[Yunan Setiawan Suwandono]]>;
<![CDATA[Eko Budi Djatmiko]]>;
<![CDATA[Murdjito Murdjito]]>;
<![CDATA[Abdul Ghofur]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i3.9955
<![CDATA[This research discusses the operability of vertical acceleration in the helideck. The experiment was carried out at the Maneuvering and Ocean Engineering Basin (MOB) facility of the BPPT-ITS Hydrodynamics Technology Center. The model being tested is the catamaran type with a scale of 1:36 to the original scale. Experimental testing using random waves with a Pierson-maskowitz spectrum with Hs = 2.5 and Hs = 6.37 m. The helideck only performs surge sway and heave tests. Meanwhile, numerical analyzes the effects of regular waves at heading 00 450 900 1350 1800 and obtained RAO for Heave, Roll, Pitch movements. For the analysis of landing operability at Helideck using the Olson and Marine criteria, where the limit of wave height according to Olson is obtained, namely for the incoming wave direction of 00, 900,1800, it should not be done more than 3 meters of wave height, while for conditions 450 and 1350 should not be above 4 meters. . For the HCA category, the critical condition when the direction of the wave of 900 with a wave height of 2 meters. At an altitude of 4 meters is the limit of the wave direction 00 450 1350 1800.]]>
<![CDATA[Experimental Study and Numerical Analysis of Floating Crane Catamaran Mooring Tension in Intact and Damage Conditions Using Time-Domain Approach ]]>
<![CDATA[Mochamad Hanif Rafi’i]]>;
<![CDATA[Eko Budi Djatmiko]]>;
<![CDATA[Murdjito Murdjito]]>;
<![CDATA[Erdina Arianti]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i3.9957
<![CDATA[Floating Crane Catamaran equipped with a mooring system to keep stable while operating. During operation, wave load causes tension on the mooring system. In this study, the tension of the mooring system was analyzed using experimental studies and numerical analysis with intact and damaged mooring conditions. Experimental studies were carried out by simulating a physical model in the Ocean Basin Maneuvering Laboratory, BTH-BPPT. While numerical using related software. Mooring tension analysis is carried out using the frequency domain approach which refers to the API RP 2SK rules. The sum of the average tension, significant low frequency tension and maximum wave frequency tension is the maximum tension of the mooring system. The low frequency tension and wave frequency tension is obtained by the low-band-pass filter process. The stochastic value is obtained by the FFT of low frequency and wave frequency tension. The results of maximum tension from experimental and numerical at intact conditions, wave headings 90°, Hs 2.5 m, are 373.7 kN and 441.6 kN and at Hs 6.37 m are 565.6 kN and 1741.5 kN. In the damaged condition, wave heading 90°, Hs 2.5 m, the maximum tension is 863.9 kN and 2113.3 kN.]]>
<![CDATA[Local Stress Analysis in the Chain Link of Mooring Line That Had Diameter Degradation ]]>
<![CDATA[Rafliansyah Azhar Putera]]>;
<![CDATA[Eko Budi Djatmiko]]>;
<![CDATA[Murdjito Murdjito]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i3.9952
<![CDATA[Mooring systems are used to moored ships at a particular area. One of its type is SPM by using a buoy. The system generally uses chains used to tie buoys to the seabed. However, chains that are used continuously can experience degradation in the diameter of the chain connection. The degradation experienced by the connections between the chains will certainly affect the local ( von Mises stress). According to ABS rules, the amount of local stress or von Mises stress that occurs on an object must not exceed 90% of the yield strength of the material. Therefore, it is necessary to do a local stress analysis to determine the extent of degradation of the diameter of the chain connection so that the local stress value does not exceed that allowed. The largest mooring tension value that occurs in the mooring system is 1838,252 kN. The results show that if the chain connection is subject to a tension of 1838,252 kN, the diameter degradation that occurs in the chain connection must not exceed 15% of the initial diameter so that the local or von Mises stress does not exceed 369 MPa (90% of the yield strength of the material 410 MPa).]]>
<![CDATA[Risk Based Inspection using API RP 580 and DNV RP F116 Towards Free Spanning Pipelines ]]>
<![CDATA[Yoyok Setyo Hadiwidodo]]>;
<![CDATA[Iftinaniffah Qonitah]]>;
<![CDATA[Daniel Mohammad Rosyid]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 2 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i4.10929
<![CDATA[The free span that occurs in the subsea pipeline can cause fatigue due to vortex induced vibration and local buckling. From the risk of failure that may occur, a risk-based inspection scheduling required. The 14" Underwater pipe belongs to PT. The X located in the Madura Strait is used to transmit gas from the CPP to ORF with a length of 65 km which has 554 free spans. In scheduling inspections, the commonly used codes are API RP 580 and DNV RP F116. This journal will discuss the difference between these two codes. Reliability calculations use Monte Carlo simulation with VIV failure mode and local buckling failure mode. The consequences of failure are reviewed on safety, environmental and asset aspects. API RP 580, shows the environmental aspect and the safety aspect of both modes of failure has the next inspection in 6 years, while the asset aspect is 3 years. At DNV RP F116, scheduling inspection of safety aspect on both modes is 3 years and environmental aspects is a year later, while the asset aspect would be better to change the pipe]]>
<![CDATA[Wave Transmission Analysis on Hexagonal Shape Floating Breakwater ]]>
<![CDATA[Sujantoko Sujantoko]]>;
<![CDATA[Haryo Dwito Armono]]>;
<![CDATA[Wisnu Wardhana]]>;
<![CDATA[Dedi Kurniawan]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 2 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i4.10934
<![CDATA[Coastal areas have many benefits for activities, such as port construction, fishing activities, recreation areas, resource utilization, alternative energy-producing places, etc. However, many factors limit this use due to water wave activity, such as storm surges and the potential for tsunamis. These factors also cause abrasion and coastal erosion that can damage the coastal environment. To overcome this problem, it can be done by building a coastal protective structure, one of which is a floating breakwater. In this study, analysis of wave transmission on a hexagonal floating breakwater will be carried out to determine the effectiveness of its performance. The wave transmission test on the floating breakwater was carried out with variations of irregular waves (Jonswap spectrum) and mooring angles. The position of the wave probe is set at 100 cm and 220 cm behind the structure. The largest transmission coefficient occurs at a mooring angle of 30o in both scenario 1 and scenario 2. The smallest transmission coefficient value is at an angle of 60o in both scenarios of wave probe placement. The plotting results show that the transmission coefficient is directly proportional to the period and height of the incident wave and vice versa the transmission coefficient is inversely proportional to the steepness of the wave]]>
<![CDATA[Experimental Study and Numerical Analysis of Crane Operability in Floating Crane Catamaran ]]>
<![CDATA[Rizky Arrico Farhan]]>;
<![CDATA[Eko Budi Djatmiko]]>;
<![CDATA[Murdjito Murdjito]]>;
<![CDATA[Abdul Ghofur]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 2 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i4.10930
<![CDATA[Crane vessel is a floating structure equipped with accommodation facilities and one or more cranes to do work in the field. Crane vessel continue to be developed so that they can lift large structures and operate safely in certain environmental conditions. The work that is usually done by crane vessel is to lift heavy or light loads from land to ship, from ship to land, from ship to sea, from sea to ship, and from ship to ship. The process of moving loads carried out by a crane vessel usually called the lifting process. In carrying out its work, a crane vessel is limited by certain criteria for safety reasons. One of them is the criterion that limits the heave motion at the end of the crane boom and roll and pitch motion of the crane vessel. In this final project, an experimental study and numerical analysis of crane operability were carried out on catamaran hulled crane vessel. Experiments were carried out at the Balai Teknologi Hidrodinamika BPPT and numerical analysis using the MOSES software. According to the criteria used, namely Operational Limitations of Offshore Crane Vessels, cranes on floating crane catamaran have the highest operability when the vessel heading is 0o to the direction of the incoming waves, which is up to Hs 1.45 m.]]>
<![CDATA[Comparative Analysis of FCAW, and GMAW Welding With Heat Input Variations on A36 Steel Against Vickers Hardness Test and Macrostructure ]]>
<![CDATA[Herman Pratikno]]>;
<![CDATA[Nugraha Adhi Pahlawan]]>;
<![CDATA[Wimala Lalitya Dhanista]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 2 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i4.10931
<![CDATA[In offshore building construction, a precise welding method is needed on A36 steel, where A36 steel is one of the main materials in the fabrication process of offshore buildings. In this study a comparison of the results of the welding GMAW and FCAW with variations of the heat input on the A36 steel to the Hardness test, and the macrostructure test and the selection of the most appropriate method based on the results of the mechanical test analysis. The heat input variations used are GMAW 1.50 kJ / mm and 2.03 kJ / mm while for FCAW 1.90 kJ / mm and 2.30 kJ / mm. The results of this study are the best hardness test results are the FCAW welding method with a heat input of 2.30 kJ / mm with an average ultimate strength of 149.06 HVN, in the macro test the results show that the greater the heat input, the wider the HAZ area, this is shown by welding FCAW heat input 2.30 kj / mm which has a HAZ width area of 20 mm.]]>
<![CDATA[Fatigue Life Analysis of Mooring System: The Effect of Asymmetry Mooring System Configuration on Single Point Mooring ]]>
<![CDATA[Revy Maghriza]]>;
<![CDATA[Eko Budi Djatmiko]]>;
<![CDATA[Murdjito Murdjito]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 2 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i4.10932
<![CDATA[This journal explains the fatigue life analysis of anchor chain in the stand-alone single point mooring by comparing the 4x1 asymmetric and symmetrical mooring system configurations to determine whether the effect of the asymmetrical mooring system configuration on the fatigue life of the anchor chain is related to the length of the mooring lines, the pretensions of the mooring lines, and the angle of spread. The analysis was reviewed on the condition of ULS and FLS environmental loading based on API RP 2 SK code using Orcaflex with 3 hours of time- domain simulation. In the ULS condition, the symmetrical configuration can withstand environmental loads better in the direction of 0o and 180o with the generated maximum tension and maximum offset value smaller than the result from asymmetrical configuration. While the asymmetrical configuration can withstand environmental loads better in the direction of 90o and 270o with the generated maximum tension and maximum offset value smaller than the result from symmetrical configuration. In the FLS condition, the asymmetrical configuration has a longer minimum fatigue life and design life of anchor chain than the symmetrical configuration. This happens because of the spread angle of the mooring line, the length of the mooring line, and the pretension of the mooring line]]>
<![CDATA[Effect Analysis on Coating Methods and Corrosive Media Variations toward Adhesion Strength, Corrosion Rate, and Metallography of ASTM A36 Steel with Polyurethane Coating ]]>
<![CDATA[Herman Pratikno]]>;
<![CDATA[Inaya Krista Pradyptia]]>;
<![CDATA[Hasan Ikhwani]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 2 (2021) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j2580-0914.v4i4.10933
<![CDATA[Corrosion can cause material damage due to the material’s reaction with the environment. Corrosion will affect materials on construction, including metal material, thereby reducing the strength and the construction life, especially in a corrosive environment. The most effective and economical corrosion control is coating. The right coating application method will result in good bonding of the paint with the material, so that the corrosion protection will be better. This research used the ASTM A36 carbon steel material and polyurethane coatings. The purpose of this study is to determine the adhesion strength and corrosion rate by varying the application methods, namely brush, roll, and spray. In the pull-off test, the highest value of adhesion strength was obtained in the spray coating method with an average value of 20,82 MPa. Whereas in the three-electrode cell testing, the lowest corrosion rate using NaCl corrosive media was found in the spray coating method with a value of 0.000025402 mmpy and the lowest corrosion rate using FeCl3 corrosive media was found in the spray coating method with a value of 0.00182 mmpy.]]>
<![CDATA[Gorlov Water Turbine Application in Ambon, Kepulauan Maluku; A Hypothetical Project ]]>
<![CDATA[Wisnu Wardhana]]>;
<![CDATA[Zahra Aisyiyah Rahayu]]>;
<![CDATA[Shade Rahmawati]]>
<![CDATA[ International Journal of Offshore and Coastal Engineering (IJOCE) Vol 6, No 1 (2022) ]]>
Publisher : <![CDATA[DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS ]]>
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DOI: 10.12962/j25800914.v6i1.13150
<![CDATA[As energy demand increases, it must be balanced with sufficient energy sources to support the growth of Indonesia's electrification ratio. No exception with the development of energy demand and supply on Ambon, Maluku Islands. This study uses a Renewable Energy Power Plant, a water turbine that uses ocean currents from the flow path of an artificial canal plan in Ambon, Maluku Islands. The shape of the area is interesting things to make an artificial canal as a flow path for ocean currents from the different height at that location. Due to the height difference cannot be determined with certainty, in this study, the authors vary the height difference between the sea in the east and west, it's 1m to 5m. Current modelling uses a numerical approach using the Surface-Water Modeling System (SMS) 8.1 software simulation. Then the average current velocity in the canal in each height variation obtained. The experimental data from journal references are used in calculating the turbine torque for a full-scale afterwards adjusted to the current speed generated in each variation. The turbine with the greatest torque is selected, owned by the 4-blades Gorlov NACA0012 with 25% efficiency and 9.5m turbine diameter totalling 1 unit.]]>
