• Journal of Advanced Research in Ocean Engineering
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• v.4 no.3
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• pp.115-123
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• 2018

This study was carried using the new approach method to design appropriately the Loading Arm length and the alarm setting according to ship movements on Loading and Unloading marine Berth. The quasi-static mooring analysis was performed to estimate 110,000DWT ship's movements based on environmental conditions such as wind, current and wave. The mooring motion of the ship is very important to determine the loading arm scope, and in this case, the operation condition is performed on the ship without considering the damaged condition of the mooring line because the ship movement in case of damage is larger than intact, and all operations are stopped, the loading arm being released due to control system. From the result of mooring analysis, motion displacements, velocities and accelerations were simulated. They were used to simulate the maximum drifting speeds and distances. The maximum drifting speeds were checked to be satisfied within drifting speed limits. The total maximum drifting distances were simulated with alarm steps of the new approach method. Finally, the loading arm envelopes using the total maximum drifting distances were completed. Therefore, it was confirmed that the new approach method for loading arm envelopes and alarm settings was appropriate from the above results. In the future, it will be necessary to perform the further advanced dynamic mooring analysis instead of the quasi-static mooring analysis and to use the precise computer program analysis for various environments and ship movement conditions.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.435-446
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• 2016

In this study, hydrodynamic and mooring analysis for LNG FSRU moored by an internal turret with 9 mooring lines are numerically performed using commercial softwares, Hydrostar and Ariane. Met-ocean combinations for screening method are taken from wave governed condition(BV Rule Note NR 493) with relative heading between wave and wind between −45° and +45° and relative heading between wind and current between −30° and +30°. Extreme mooring analysis and sensitivity analysis are performed for intact and damaged (=one line missing) conditions and the parameters for sensitivity analysis are wave peak period, peak enhancement factor and line pretension. In the viewpoint of the design tension in mooring line, chain diameter is designed to satisfy safety factor for each conditions. As the chain diameter is increased from 152mm to 171mm, the designtension is reduced while the minimum breaking load is increased.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.344-352
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• 2019

A coupled analysis was performed between the riser to develop oil and gas in ultra-deepwater and the moored floating body. In general, the safety of the riser is conservatively evaluated by considering the maximum offset excluding the coupled analysis with the floating body. In this study, the safety of the riser was analyzed by considering the coupled motion analysis of the moored floating body. The riser is considered steel lazy wave riser (SLWR) applied in the deep sea, and the floating body is determined to FPSO. The methodology was presented on coupled and uncoupled analysis. The coupled effects were analyzed according to the incident wave headings in intact and damaged conditions of mooring lines. The tension of mooring lines, the motion of the floating body, and riser responses were analyzed according to the loading conditions.

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.5
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• pp.487-495
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• 2016

In the offshore project such as semi-submersible FPU and FPSO, the free fall type life boat called TEMPSC (Totally Enclosed Motor Propelled Survival Craft) has been installed for the use of an emergency evacuation of POB (People on Board) from the topside platform. For the design of life boat arrangement for semi-submersible FPU in the initial design stage, the drop height and launch angle are required fulfill with the limitation of classification society rule and Company requirement, including type of approval as applicable when intact and damage condition of the platform. In this paper, we have been performed the numerical studies to find proper arrangement for the life boats consider drop height in various environmental conditions such as wave, wind and current. In the calculations, the contributions from static and low frequency (LF) motions are considered from the hydrodynamic and mooring analysis as well as damage angle from the intact and damage stability analysis. Also, Air-gap calculation at the life boat positions has been carried out to check the effect on the life boat arrangement. The air-gap assessment is based on the extreme air-gap method includes the effect of 1st order wave frequency (WF) motions, 2nd order low frequency roll/pitch motion, static trim/heel and set down.