EVALUATION OF EFFECTIVE WORKING DAYS CONSIDERING MOORED SHIP MOTION IN POHANG NEW HARBOR

Moonsu Kwak, Chongkun Pyunan

Abstract


This study proposes an estimation method for allowable wave heights for ship loading and unloading and evaluation of effective working days, considering moored ship motion that is affected by ship sizes, mooring conditions, and wave periods and directions. The method’s validity was examined with wave field data at pier 8th in Pohang New Harbor. The wave field data, obtained when downtimes had occurred, indicated wave heights of 0.10‒0.75 m and wave periods of 7‒13 s for ship sizes ranging between 800‒35,000 ton in weight. On the other hand, the estimated results for allowable wave heights for ship loading and unloading using this method yielded wave heights of 0.19–0.50 m and wave periods of 8‒12 s for ship sizes of 5,000, 10,000 and 30,000 ton in weight. Thus, this method reproduced well the field data responses of ships of various sizes and at different wave periods. But the allowable wave heights proposed by Korea’s technical standard are did not respond to various the ship sizes and wave periods. And the results of this method tended to decrease in 16–62 percent when have considered long wave, and it is decreased in 0‒46 percent when did not consider long wave than Korea’s technical standards in case of the ship sizes of 5,000‒30,000 ton, wave period of 12 s and wave angle of 75 degree. The allowable wave heights for ship loading and unloading proposed by Korea’s technical standards have indicated that overestimated for ships smaller than 10,000 ton in weight. On the other hand, the percentage rate of effective working days accounting for ship motion at pier 8th in Pohang New Harbor was 6.5 percent less compared to the corresponding results that did not consider ship motion.

Keywords


Allowable wave height for ship loading and unloading, Oscillation quantity of moored ship, Pohang New Harbor

Full Text:

PDF

References


Ann, S. P. (1986). Analysis of Moored Ship Motion Using Three Dimensional Source Distribution Method, Master’s Thesis, Seoul National University, Seoul Korea (in Korean).

Ann, S. P. and Rhee, K. P. (1987). “The Hydrodynamic Interaction Effects between Two Barges on the Motion Responses”, Journal of the Society of Naval Architects of Korea, Vol. 24, No. 1, pp. 29-34 (in Korean).

Bruun, P. (1981) Port Engineering, 3rd Edition, Gulf Pub.

Cho, I. H. and Choi, H. S. (1992). “Wave Responses and Ship Motions in a Harbor Excited by Long Waves (I)”, Transactions of the Society of Naval Architects of Korea, Vol. 29, No. 2, pp.38-47.

Cho, I. H. and Choi, H. S. (1993). “Wave Responses and Ship Motions in a Harbor Excited by Long Waves (II)”, Transactions of the Society of Naval Architects of Korea, Vol. 30, No. 1, pp.87-93.

Cho, I. S., Kong, K. Y. and Lee, Y. S. (2006). “A Time Domain Analysis of Moored Ship Motions Considering Tsunami Resonant Effects”, Proceedings of the Spring Conference on Korean Institute of Navigation and Port Research, Korean Institute of Navigation and Port Research, Vol. 30,No 1, pp.191-197 (in Korean).

Demirbilek, Z. and Panchang, V. (1998). CGWAVE : A Coastal Surface Water Wave Model of the Mild Slope Equation. Technical Report CHL-98-xx, U.S. Army Corps of Engineers, pp.6-11.

Jeong, W. M., Ryu, K. H., Beak, W. D. and Choi. H. J. (2011). “Downtime Analysis for Pohang New harbor through Long-term Investigation of Waves and Winds”, Journal of Korean Society of Coastal and Ocean Engineers, Vol. 23, No. 3, pp.226-235 (in Korean).

Kubo, M., Saitou, K. and Sakakibara, S. (1988). “Application of a strip method to the hull motion of a quay-front moored vessels”, Proceedings of the 35th Japanese Conference on Coastal Engineering, Japan Society of Civil Engineers, Vol. 35, pp.682-686 (in Japanese).

Kubo, M., Saito, K. and Oki, T. (1993). “Approximate Calculation of Ship Motions under the Prevention System of Ship Separation from Quay Wall”, Journal of Japan Institute of Navigation, Vol. 89, pp.15-21 (in Japanese).

Kubo, M. and Sakakibara, S. (1995). “Effects of Long Period Waves Caused by Wave Groups and Harbor Oscillation in Computation of Wharf Operation Efficiency”, Proceedings of Coastal Engineering, Japan Society of Civil Engineers, Vol. 42, pp.931-935 (in Japanese).

Kwak, M., Chung, J., Ann, S. and Pyun, C. (2006). “Estimation of Harbor Operating Ratio Based on Moored Ship Motion”, Journal of The Korean Society of Civil Engineers, Vol. 26, No.6B, pp.651-660 (in Korean).

Kwak, M. S., Moon, Y. H. and Pyun, C. K., (2013). “A Study on Analysis of Moored Ship Motion Considering Harbor Resonance”, Journal of the Korean Society of Civil Engineers, Vol. 33, No. 2, pp.595-608 (in Korean).

Mollen, W., Ligteringen, H., Lem, J. C. vander, Waal, J. C. M. de (2003). “Behavior of a Moored LNG Ship in Swell Waves”, Journal of Waterway, Port, Coastal, and Ocean Engineering, ASCE, Vol. 129, No. 1, pp.15-21.

Pohang Regional Maritime Affairs and Port Office (2010). Field Investigation Report for Swell Analysis and Improvement Measure Making of Downtime in Pohang New Harbor, Report of Pohang Regional Maritime Affairs and Port Office (in Korean).

Rafael, G., Eduardo, G., Fernando, P. (1998). “Utilization of moored vessels in hydraulic models of harbors”, Coastal Engineering, ASCE, pp.2979-2990.

Sakakibara, S., Saitou, K. and Kubo, M. (2001). “A study on Long-Period Ship Motions in a Harbor Induced by a Resonant Large Roll Motion Under Long-Period Waves”, Proceedings of ISOPE, The International Society of Offshore and Polar Engineers, Stavanger Norway, pp.326-333.

Ueda, S. and Shiraishi, S. (1988). The allowable ship motions for cargo handling at wharves. Vol. 27, No. 4, Technical report of port and harbour research Institute, Japan, pp.3-61 (in Japanese)..

Ueda, S., Shiraishi, S., Oshima, H. and Asano, K. (1994). “Proposal of Allowable Wave Height and Wharf Operation Efficiency Based on the Oscillations of Ships Moored to Quay Walls”, Proceedings of Coastal Engineering, Japan Society of Civil Engineers, Vol. 41, pp.916-920 (in Japanese).

Yeun, A. F., Burke, M. G. and Leung, T. C. (1986). “Ship Motion Study for the 2010 and 2020 Plan in the San Pedro Bay California”, Coastal Engineering, ASCE, pp.2742-2755.




DOI: https://doi.org/10.9753/icce.v34.management.20