貨櫃輪平靠港埠碼頭繫纜繩斷纜及絞機預張力之分析

ANALYSIS OF MOORING FAILURE AND WINCH PRETENSION IN VESSELS BERTHING

台灣由於地理位置及位處亞熱帶氣候，每年夏秋之際易有侵襲台灣的颱風，其瞬間強風與港內大浪將對港埠中繫泊之船舶有造成危害之風險，對於停靠在港內之船隻將造成劇烈的搖晃。颱風伴隨而來的極端海象條件(強風、巨浪)也提升港口維護船舶停靠繫泊的困難。並且在極端氣候條件下，船舶繫泊可能產生斷纜的機會將會大幅提升。本研究主要使用數值軟體OrcaFlex進行數值模擬，藉以分析港埠碼頭平靠繫泊之貨櫃輪的繫泊安全，並在OrcaFlex中進行繫纜纜繩張力、絞機預張力及防舷材回復力之計算。本研究將透過分析繫纜張力、船體二維漂移軌跡以及五十年回歸期颱風波浪條件，並在模擬中建置五種不同的絞機預張力去分析不同預張力對纜繩張力及船體漂移軌跡的影響，並利用頻域能量密度圖，去分析防舷材、纜繩、船體漂移的能量密度變化，在分析過後建立一套纜繩選定、預警標準應用及繫纜方法選定之方法，除減少船舶斷纜意外及降低極端值纜繩張力之產生，研究成果可作為港埠安全應對當遭遇極端海氣象時安全維護標準之參考。

Taiwan is frequently affected by typhoons during the summer and autumn. The sudden strong wind from typhoons pose hazards to vessels moored in harbors. When facing extreme climates, there is a significantly increased risk of mooring failure when vessels are moored. Therefore, this study utilizes numerical modeling tool, Orcina OrcaFlex, to simulate and analyze the tension of mooring, the two-dimensional motion trajectories of vessels, and the 50-year return typhoon wave conditions. The simulation incorporates five different winch pretension settings to analyze the im-pact of different pre-tension levels on mooring tension and ship motion trajectory. Additionally, the study utilizes frequency domain energy density diagrams to analyze the energy density variations of fenders, mooring, and ship motion. Based on the analysis, the aim is to establish a method for selecting moorings, applying warning standards, and determining winch pre-tension. To understand how to reduce the occurrence of extreme tension in individual mooring during berthing, simulations are conducted under various wave height and wind speed in regular waves. The characteristics of maximum tension in eight moorings are explored. Additionally, simulations are performed under different wave and wind directions to investigate the three-dimensional motion characteristics (heave, pitch, sway, roll, yaw, surge) of container ships. Furthermore, this study discusses the density diagrams of fender forces, mooring tension and vessel motions facing regular waves and fifty-year return wave conditions with five different winch pretensions for investigation of harbor safety.