Analisis Stabilitas Intact Sudut Besar terhadap Perubahan COG Crane Barge saat Operasi Heavy Lifting

Hafshah, Nailatul Fadhilah (2024) Analisis Stabilitas Intact Sudut Besar terhadap Perubahan COG Crane Barge saat Operasi Heavy Lifting. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Proses eksplorasi dan eksploitasi potensi minyak dan gas di lepas pantai membutuhkan peralatan penunjang salah satunya adalah topside platform yang dalam instalasinya menggunakan metode lifting. Crane barge sebagai floating crane vessel dapat dioperasikan untuk operasi heavy lifting yang mampu mengangkat beban hingga ribuan ton. Beban yang diangkat berdampak pada perubahan titik pusat massa (COG) yang akan mempengaruhi stabilitas crane barge selama operasi lifting berlangsung. Skenario yang digunakan dalam analisis stabilitas penelitian ini adalah perputaran sudut crane secara horizontal dari sisi starboard hingga sisi portside crane barge dan variasi tinggi draft dari 75% hingga 100% kondisi full load. Hasil keseluruhan loadcase stabilitas intact crane barge secara numerik memenuhi ketentuan dari IMO A.749(18). Nilai GZ maksimum terjadi pada sudut putar 90⁰ ke arah portside untuk heel 20⁰ untuk ketiga variasi draft dan draft 90% terjadi saat heel 25⁰. Korelasi perubahan draft terhadap besar nilai GZ adalah semakin tinggi draft yang diaplikasikan maka diperoleh nilai GZ yang semakin kecil. COG setelah analisis stabilitas mengalami perubahan yang signifikan pada setiap variasi draft sedangkan terhadap perubahan sudut putar perubahan hanya terjadi pada besar VCG crane barge. Perbandingan hasil perhitungan analisis stabilitas crane barge secara numerik dan analitik memiliki koreksi nilai error yang telah memenuhi ketentuan dari IACS UR L5 yaitu dibawah ±5%. Nilai error terbesar terjadi pada sudut kemiringan 60⁰. Perbedaan stabilitas sudut kecil dan sudut besar adalah sudut kecil hanya dipengaruhi oleh besar kemiringan sudut sin θ sedangkan pada stabilitas sudut besar akibat kemiringan yang berlebih nilai GZ juga dipengaruhi tan θ. GZ pada sudut kecil memiliki nilai GM sebesar 14.7 meter berselisih 0% dengan kondisi initial sedangkan pada sudut besar memiliki GM terkecil 0.89 meter diperoleh selisih hingga 0.9% terhadap kondisi initial.
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Exploration and exploitation of offshore oil and gas potential requires supporting equipment, one of which is topside platform. Platform installation process uses lifting method for each module such as topside. Crane barge as a floating crane vessel can be operated for heavy lifting operations that capable to lifting loads up to thousands of tons. Lifted objects have an impact on changes of the center of gravity (COG) which will affect the crane barge stability during lifting operations. The scenario used in this research of intact stability analysis is crane turning horizontally from starboard side to the port side of the crane barge and variation of draft from 75% full load to 100% full load conditions. Result of crane barge intact stability analysis for entire loadcase in numerical method meet the IMO A.749(18) requirements. Maximum GZ (Righting arm) value occurs when the turning angle is 90⁰ to the portside at heel angle of 20⁰ for all three draft variations and 90% draft occurs when the heel is 25⁰. The correlation of draft changes to GZ value is that the higher applied draft will obtain the smaller GZ value. COG after stability analysis have significant changes in each draft variation, while changes in the turning angle only occur at VCG of the crane barge. Result comparisons between numerical and analytical calculation method has corrected error values that have met IACS UR L5 requirements which is below ±5%. The largest error occurs at a heel angle of 60⁰. The difference between small angles stability and large angle stability is that small angles are only affected by heeled angle of sin θ, while in large angles stability not only affected by sin θ, but also angle of tan θ, it is caused by excessive heel. GZ at small angles has a GM value of 14.7 meters with a 0% difference with the initial conditions while at large angles has the smallest GM of 0.89 meters obtained a difference of up to 0.9% against the initial conditions.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Crane Barge, Intact Stability, Large Angle Stability, Lifting
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1665 Offshore structures--Materials. V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM1 Ballast (Ships) V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM761 Stability of ships
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Nailatul Fadhilah Hafshah
Date Deposited:	26 Jul 2024 01:16
Last Modified:	26 Jul 2024 01:16
URI:	http://repository.its.ac.id/id/eprint/108951

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