A study of cargo safety operation of cape size bulk carrier

• Main Authors: Lin, Terq-Der, 林正德
• Other Authors: Tien, Wen-Kwo
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/72210523968977185121

碩士 === 國立臺灣海洋大學 === 商船學系 === 103 === Transportation is the cradle of human civilization. Vessels are an important means of sea transport, and freight contracts are the main operating businesses for shipping companies. In early times, the tonnage of vessel was small; nowadays, thanks to the advance of technology, tonnage is getting greater and greater, with four hundred thousands of tonnage for bulk carriers. The building of loading decks and ports is getting larger in size and commodity loading faster in speed. The requirements for security examination of loading metacentric height, shearing force and bending moment on cargo transportation are hence very strict. This study focused on the operation of loading of bulk carriers, how to complete the transport task successfully and the protection of marine environments to prevent marine pollution and ensure the safety of the vessels, cargo and human life. The enlargement of bulk carriers has become the current trend in sea freight transportation. For this reason, this study investigated and analyzed the need of cargo stowage variations by calculating the cargo load based on the data from onboard local loading calculator No. 158 on a cape size bulk carrier in one trip charter voyage and checking cargo weights using Excel program and the loading manual for comparison. From the calculations of cargo load distributed to each hold in the carrier in four different cargo loading scenarios A,B,C and D, the following key conclusions were made. Same cargo calculations by position (in scenarios A, B, C, and D): (1) Draft 17.02 even keel; (2) Sea condition: Ocean; (3) Displacement 184,381T; (4) Measured specific gravity of sea water 1.025; (5) Propeller immersion ratio 151.7%. Different cargo calculations by position: (1) In scenario A, homogeneous hold loading condition, the cargo was distributed in 9 holds, resulting in -35.01% and -28.04% each of the maximum values for shear force and bending moment, and the transverse metacentric height corrected for free surface effect at 9.37m and The cargo loaded in 9 holds was within the permissible GoM and weight limit. (2) In scenario B, alternate hold loading condition, the cargo was distributed in holds 1, 3, 5, 7 and 9 resulting in -97.34% and 72.92% each of the maximum values for shear force and bending moment and the transverse metacentric height corrected for free surface effect at 6.90m. The cargo loads in holds 1, 3, 5, 7 and 9 were closer to the permissible weight limit and caused more stress on the steel plates, posing a higher risk to old ships. (3) In scenario C, block hold loading condition，the cargo was distributed in holds 1, 3, III 4, 5, 6, 7 and 9 resulting in 90.9% and 54% each of the maximum values for shear force and bending moment, and the transverse metacentric height corrected for free surface effect within the permissible limit, 8.28m. The cargo loads in holds 1, 4, and 6 were closer to the permissible weight limit and caused more stress on the steel plates, posing a higher risk to old ships. (4) In scenario D, block hold loading condition, the cargo was distributed in holds 1, 3, 4, 6, 7 and 9, resulting in 109.08% and 104.48% each of the maximum values for shear force and bending moment, which exceeded 100% of the maximum values for both and would cause the ship to be damaged and break in this spot, while the transverse metacentric height corrected for free surface effect was within the permissible limit, at 7.72m. The load in hold 1 exceeded the permissible weight limit, whereas the cargo weight in hold 5, which was not loaded with cargo, did not meet the safety minimum requirement of 6,263 - 36,097 MT. This means more stress on the steel plates and the subsequent occurrence of damage and breakage in this spot. This study verified computer features of cargo loading. By swiftly providing accurate safety data for cargo loading, one can reduce unnecessary waste of time on complicated manual calculations. Time saved is money earned. It is crucial for cargo safety check and requirement and the development and training of personnel in the future.