Examination of the intact stability and the seakeeping behaviour

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1 Introduction ˆ During the accident the waves had a signicant period of approximately T S = 9 ... 10 s and a signicant wave height of H 1/3 = 7.5 m. ˆ The encountering angle between the vessel and the waves was about 120 ◦ ... 150 ◦ (with 0 ◦ from astern). ˆ The ship operated at low speeds of about v = 2 ... 4 kn. ˆ The ship was lightly loaded, which resulted in KG = 15.647 m (free surface correction included) and GM corrected = 7.712 m. ˆ The maximum rolling angle was about 35 ◦ . ˆ The maximum transversal accelerations on the bridge exceeded 1.0 g. ˆ One crew member was killed, one heavily injured and several slightly injured. ˆ No noticeable damages to the vessel's hull. 1.1.2 Accident of a 2468 TEU container vessel [2] ˆ The accident happened on September 15th, 2009 during heavy weather in the South China Sea near Hong Kong. ˆ During the accident the waves had a signicant wave period of T S = 8 ... 9 s and a signicant wave height of about H 1/3 = 7 m. ˆ The encountering angle between the vessel and the waves was about 120 ◦ ... 150 ◦ . ˆ The ship operated at low speeds of about v = 2 ... 3 kn. ˆ The ship was lightly loaded which resulted in KG = 9.696 m (free surface correction included) and GM corrected = 5.627 m. ˆ The documented longitudinal bending moment was higher than the admissible value. ˆ The maximum rolling angle was about 30 ◦ . ˆ The maximum transversal accelerations on the bridge exceeded 1.2 g. ˆ One crew member was killed. ˆ Heavy damages to the vessel's hull occurred. 1.1.3 Accident of a 2500 TEU container vessel [3] ˆ The accident happened on October 16th, 2009 during heavy weather in the North Sea near Borkum. ˆ During accident the waves had a signicant wave period of T S = 9 ... 10 s and a signicant wave height of about H 1/3 = 7 m. ˆ The encountering angle between the vessel and the waves was about 120 ◦ ... 130 ◦ . ˆ The ship operated at low speeds of about v = 5 kn. ˆ The ship was lightly loaded which resulted in KG = 10.45 m (free surface correction included) and GM corrected = 4.56 m. 2
1.2 Following objectives for the diploma thesis ˆ The maximum rolling angle was about 30 ◦ . ˆ The maximum transversal accelerations on the bridge exceeded 1.0 g. ˆ One crew member was heavily injured. ˆ No damages to the vessel's hull occurred. 1.2 Following objectives for the diploma thesis Due to the many similarities between the above mentioned three accidents, the question arises, whether other conventional container vessels also would encounter such high rolling angles and accelerations on the bridge under the accident conditions named above. According to the actual intact stability code IMO A.749(18)[4], an approved trim and stability booklet for each ship has to contain some standard loading conditions. Of those, the ballast arrival loading condition matches the loading condition of the ships in accident best. In this loading condition the ship operates without cargo, with 10 % bunker and stores as well as enough ballast water for sucient immersion of the hull. The propeller has to be immersed for adequate propulsion. Additionally the fore ship has to be immersed suciently to reduce slamming forces on the forward bottom shell. This results in a small KG and respectively a high GM. Furthermore lled ballast water tanks in the fore or aft part of the ship cause high, longitudinal bending moments to the ship's hull. The ship has to be ballasted, so the maximum allowed bending moment is not exceeded. Container ships in the ballast arrival loading condition operate always with a relatively high negative trim. Negative means, the ship's draught at the aft perpendicular is higher. The ballast arrival loading condition is mandatorily indicated to be a seagoing condition. Therefore the scope of this thesis is to examine, if container vessels in ballast arrival loading condition have an increased risk of accident in heavy seas due to the design of this specic ship type. For this reason a larger number of container vessels of various size is analysed in the ballast arrival loading condition . The goal is to determine the seakeeping behavior for each vessel when it is encountering the three aforementioned accident situations. So the maximum rolling angle and the maximum transversal acceleration on the bridge are calculated, to estimate the risk of accident. All needed calculations are performed with the ship design software E4, which is available at Hamburg University of Technology (TUHH). A detailed description of the utilised methods can be found in chapter 2. In addition approaches to reduce the risk of accident shall be provided, examined and evaluated. 3
Page 1: Dezember 2010 SCHRIFTENREIHE SCHIFF
Page 5: 1st Examiner: Prof. Dr.-Ing. Stefan
Page 9 and 10: Contents List of Figures List of Ta
Page 11 and 12: Contents A.14 Vessel No. 14 . . . .
Page 13 and 14: List of Figures 2.1 Calculation mod
Page 15 and 16: List of Tables 3.1 Accident situati
Page 17 and 18: Nomenclature Symbol Unit Meaning A
Page 19: 1 Introduction In the years 2008/20
Page 23 and 24: 2 Theory 2.1 Description of the uti
Page 25 and 26: 2.1 Description of the utilised sea
Page 27 and 28: 2.1 Description of the utilised sea
Page 29 and 30: 2.2 Environmental conditions period
Page 31 and 32: 3 Data input The thesis is written
Page 33 and 34: 3.6 Free surface correction 3.6 Fre
Page 35 and 36: 3.10 Bridge height 3.10 Bridge heig
Page 37 and 38: 4 Examination For each vessel the s
Page 39 and 40: 4.2 Vessel No. 02 4.2 Vessel No. 02
Page 41 and 42: 4.3 Vessel No. 03 ˆ The documented
Page 43 and 44: 4.5 Vessel No. 05 accident situatio
Page 45 and 46: 4.6 Vessel No. 06 4.6 Vessel No. 06
Page 47 and 48: 4.7 Vessel No. 07 ˆ The stability
Page 49 and 50: 4.9 Vessel No. 09 Figure 4.16: Tran
Page 51 and 52: 4.10 Vessel No. 10 4.10 Vessel No.
Page 53 and 54: 4.11 Vessel No. 11 ˆ The limiting
Page 55 and 56: 4.13 Vessel No. 13 Figure 4.24: Tra
Page 61 and 62: 5 Evaluation Based on the determina
Page 63 and 64: 5.3 Recommendations accelerations s
Page 65 and 66: 6 Detailed examination The evaluati
Page 67 and 68: 6.1 Variation of the GM values acce
Page 69 and 70: 6.2 Rolling behavior of the large v
Page 71 and 72:
6.2 Rolling behavior of the large v
Page 73 and 74:
6.2 Rolling behavior of the large v
Page 75 and 76:
7 Conclusions Summing up the result
Page 77 and 78:
A Vessel data A.1 Vessel No. 01 Tab
Page 79 and 80:
A.3 Vessel No. 03 A.3 Vessel No. 03
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
A.11 Vessel No. 11 A.11 Vessel No.
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
B Variation of the bilge keel area
Page 95 and 96:
C Variation of the ship's speed 16
Page 97:
Bibliography [1] BSU; Federal Burea
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Examination of the intact stability and the seakeeping behaviour

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