WEKO3
アイテム
船尾トロールについての実験的考察
https://fra.repo.nii.ac.jp/records/2005629
https://fra.repo.nii.ac.jp/records/2005629c7690aa5-4e17-447b-bce2-33da92bfbe9a
| 名前 / ファイル | ライセンス | アクション |
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tokai_k_77_171.pdf
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| アイテムタイプ | 紀要論文 / Departmental Bulletin Paper(1) | |||||
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| 公開日 | 2024-05-22 | |||||
| タイトル | ||||||
| タイトル | 船尾トロールについての実験的考察 | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | Study on the Stern Trawl | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | open access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||
| 著者 |
小山, 武夫
× 小山, 武夫 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | There has been no systematic research work made on the relation between the towing powers of recently built stern trawlers and sizes of nets and gear used by the trawlers. The author has been engaged in research works to determine the fundamental requirements in the nets and gear designing suitable for trawlers. The experiments have been done by the following seven trawlers with twelve sets of nets and gear of different sizes (Figs. 1-26). The No. 3 Heian maru (314 G. T. of 1200 ps), the No. 83 Taiyo maru (1500 G. T. of 2700 ps), the No. 81 Taiyo maru (2800 G. T. of 3150 ps), the No. 82 Taiyo maru (2900 G. T. of 3150 ps), the Zuiyo maru (3000 G. T. of 3500 ps), the Shoyo maru (3400 G. T. of 4000 ps), the Kaiyo maru (2539 G. T. of 3800 ps) were built during 1964-1967 and specification is shown in Table 2. The measuring equipment is shown in Figs. 27-33, and the experimental results obtained are shown in Tables 4-9. A careful study has been pursued on the collective relation between the towing powers of the above-mentioned trawlers and the sizes of nets and gear applied, and on the resistance of the trawl nets and gear, the warp tension of net shooting and hauling, the developing force of otter boards, and other important matters for the designing. The findings are as follows, (1) Pulling power of stern trawler. While pulling a trawl, η (efficiency of propulsion) of the No. 3 Heian maru (39.80 m in all-over length) was η = 0.056 V+0.093, the No. 83 Taiyo maru (73.79 m) η = 0.081V +0.082, the No. 82 Taiyo maru (88.20m) η = 0.055 V+0. 137, the Zuiyo maru (88.20 m) η = 0.026 V+0. 24, the Shoyo maru (99.50m) η = 0.06 V+ 0.209, and V stands for towing speed (m/sec). η in the towing speed assumed to be 1.8 m/sec was 0.19 in case of the No. 3 Heian maru (39. 80 m in all-over length) 0.225 in case of the No. 83 Taiyo maru (73. 79 m in all-over length) 0.235 in case of the No. 82 Taiyo maru (82. 20 m in all-over length) 0.285 in case of the Zuiyo maru (82. 20 m in all-over length) 0.32 in case of the Shoyo maru (99.50 m in all-over length) η tends to increase as the towing speed quickens and as the ships become large (Figs. 35-36). Assuming that w (wake coefficient) of each trawler as 0.3, t (thrust reduction coefficient) of the No. 3 Heian maru (39. 80 m in all-over length) was found 0.24, the No. 83 Taiyo maru (73.79 m) 0.19, the Zuiyo maru and the No. 82 Taiyo maru (88.20 m) 0.1 and the Shoyo maru (99.50 m) 0, t tends to decrease as ships become large (Fig. 38 and Table 6). While pulling a trawl Eɴ·H·P (pulling power) is expressed as follows: Eɴ·H·P = η(B₁·H·P) E₁·H·P - Es·H·P / E₁·H·P Where E₁·H·P: Effective horsepower (the sum of gear resistance and hull resistance). B₁·H·P: Shaft horse power. Es·H·P: Hull resistance horse power. η: Efficiency of propulsion (E₁·H·P/B₁·H·P). E1 .H.P-Es.H.P The value of E₁·H·P - Es·H·P / E₁·H·P of each ship was about 0.93 at the calm sea, and 0.55 at the rough sea (head wind, Beaufort 6) but 1.31 in case of fair wind (Table 5 and Table 8). (2) Relation between shaft horse power and propeller revolution while pulling trawl. While pulling the trawl, the shaft horse power (B₁·H·P) of the main engine is proportional to cube of the propeller revolution (r.p.m) (Fig. 41). (3) Resistance of trawl net. It can be said that the resistance R (kg) of a trawl net is approximately expressed as follows (Fig. 48 and Table 11); R=Kab d/l V² Where K = Resistance coefficient is 8.0 (kg.sec²/m⁴). a = The maximum breadth of trawl net body (Fig. 46) (meter). b = The maximum length of trawl net without shrinkage (Fig. 46). d/l=In case of four-six-seam net; the average value of ratio: d-diameter of net twine, l-length of each mesh bar at side panel, 1-7 section (Fig. 46). In case of two-seam net; the average value of ratio: d-diameter of net twine, l-length of each mesh bar at upper net, 1-7 section (Fig. 46). V=Towing speed (m/sec). The resistance R includes those of floats, bobins etc. (4) Height of net mouth The relation between V (towing speed) and h (height of net mouth) of the trawl net (Figs. 10-11) is expressed as follows (Fig. 49), h = 10V⁻⁰·⁸³⁹ The height of a net mouth is kept well at more than 3 knots per hour at towing speed. (5) Developing force of an otter board. L (kg), a developing force of an otter board (Süberkrüb type), is obtained as follows ; L = 1/2 C ʟV²Sρ Where S = Area of an otter board (m²). ρ = Density of sea water (105 kg.sec²/m⁴). V = Towing speed (m/sec). Cʟ = Developing force coefficient. Cʟ of the otter board used for the experiment is approximately 0.76 in case of soft mud bottom and 1.17 sand-mud bottom (Fig. 51 and Table 13). (6) Developing distance between the frontal ends of two wings nets. W (m), the developing distance between the frontal ends of two wing nets, is calculated in the following formula (Fig. 52) ; W=k 2lᴡlₙ/lₕ+lₙ sinθ/2 + Flₙ/lₕ+lₙ Where k = Coefficient is 1.0 lw = Length of a warp (length from top rollers) (m). lₕ = Distance from the frontal end of a wing net to otter board (m). lₙ = Length of the net measured between the frontal end of a wing net and the cod head (m). θ = Angles subtended of a pair of warps. F = Interval between two top rollers (m). W of the ten kinds of the trawl-nets used for the experiment is approximately 35% of the head rope length in case of soft mud bottom and 55% sand-mud bottom. (7) Relation between developing force of an otter board and resistance of trawl net. It must be so designed that the developing force of an otter board may be 0.18 ~0.2 times the resistance of a trawl net. (8) Warp tension while shooting and hauling trawl. The structures of the otter board and the trawl net used for the experiment are shown in Figs. 12-13 and Figs. 55-56 and the warp tension meter in Fig. 30. a) Warp tension while shooting trawl. Tension of 4-5 tons was recorded on each warp while shooting (vessel speed 6 knots; shooting speed 100 m/min) at the rough sea. That increased to 10-12 tons when shooting was braked every 100-200 m for the extension of the trawl net (Fig. 57). The values of tension were nearly equal to those measured at the calm sea. b) Warp tension while pulling and hauling trawl. At the calm sea tension of 5-6 tons was recorded on each warp while pulling the trawl (warp length 500 m; pulling depth 124 m; towing speed 4 knots), and that decreased to 3-4 tons when pulling was changed in to hauling (hauling speed 90 m/min; towing speed 0.5-1.0 knots). The tension while hauling was not changed particularly when the otter boards and the net left the sea bottom (Fig. 58). It was found that at the rough sea each tension of the warps fluctuated from 4 to 8 tons in pulling the trawl (warp length 600 m; pulling depth 150 m; towing speed 4.2 knots; Fig. 59). When the otter boards and the net left the sea bottom by hauling, the warp tension fluctuated suddenly, and 24 tons on one of the paired warps and 38 tons on both ones were recorded at the maximum (hauling speed 80 m/min; towing speed 1.0 knot; Figs. 60-61). But the warp tension did not exceed 15 tons even at the rough sea when the net was hauled at the speed of 40 m/min (Fig. 62). c) Warp tension offered when fish school enters the net. The warp tension fluctuated little regardless of amount of fish to have entered the net. In this experiment the warp tension which was offered when fish (about 12 tons) entered the net was approximately the same as it was done when no fish entered it (Figs. 63-64). (9) Sinking speed of trawl-net. The sinking speed of the trawl-net is 11 m/min in case of D net (Figs. 6-7) and 17 m/min K net (Figs. 18-19). Sinking speed of the net depends on weigth of otter board (Table 19). | |||||
| 言語 | en | |||||
| 書誌情報 |
ja : 東海区水産研究所研究報告 en : Bulletin of Tokai Regional Fisheries Research Laboratory 巻 77, p. 171-247, ページ数 77, 発行日 1974-03-25 |
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| 出版者 | ||||||
| 出版者 | 東海区水産研究所 | |||||
| 言語 | ja | |||||
| 出版者 | ||||||
| 出版者 | Tokai Regional Fisheries Research Laboratory | |||||
| 言語 | en | |||||
| ISSN | ||||||
| 収録物識別子タイプ | PISSN | |||||
| 収録物識別子 | 0040-8859 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AN00156834 | |||||
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| 識別子タイプ | Local | |||||
| 関連識別子 | tokai_k_77_171 | |||||
| 著者版フラグ | ||||||
| 出版タイプ | VoR | |||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
