Trials of extension of horizontal aerial extent of tori line for the Japanese small longliners operating in the Northwest Pacific Ocean

Citation
Katsumata N, Okamoto K, Ochi D, Inoue Y (2018) Trials of extension of horizontal aerial extent of tori line for the Japanese small longliners operating in the Northwest Pacific Ocean. In: WCPFC Scientific Committee 14th Regular Session. WCPFC-SC14-2018/ EB-IP-13, Busan, Republic of Korea, p 12
Abstract

For further improvement of performance of tori line applied for the Japanese small longliners (< 24 m in Length of overall (LOA)) operating in the Northwest Pacific Ocean, we addressed extension of horizontal aerial extent of the tori line by on-land and at-sea experiments. In the on-land experiment, we compared aerial extents of two different tori lines regarding material. Furthermore, we tested 20 types of tori line through the at-sea experiment to obtain knowledge how to extend the horizontal length extent of tori line. In the on-land experiment, the tensile strength apparently increased as the connecting point of the eight cross rope tori line was moved to higher points, whereas there were not obvious differences in the strengths among the connecting point of the Dyneema tori line. In the at-sea experiment, Dyneema applied to the aerial section showed better performance to extend the aerial extent of tori line than eight cross rope. The maximum horizontal lengths of the aerial extent of tori line were 45.0 m and 76.3 m and for the eight cross rope and Dyneema aerial sections, respectively. The 75 m and 100 m Dyneema towing sections had equivalent effects in extension of the aerial extent with the eight cross rope towing sections and needed smaller drags than the eight cross rope sections. These results showed that Dyneema is a suitable material for extension of the aerial extent of tori line for the Japanese small longliners.