Studies of the Seakeeping Qualities of Bull Trawlers by Means of Field Measurements

1) The study of seakeeping qualities has remarkably progressed in recent years, accompanied by the great progress in the study of ocean waves. These studies may be considered to form a part of the theoretical background of seamanship. Concerning fishing boats, it is necessary to clarify the characteristics of their behaviors on ocean waves not only for ship\u27s stability but also for safety during fishing operaions at sea. In fact, the motions of fishing boats are affected by their fishing gear during fishing operations, and their motions in response to ocean waves are larger than those of other types of ships, e. g. a general cargo ship, in similar seaway situations. With this viewpoint in mind, researches on the seakeeping qualities of fishing boats were performed by making field measurements during fishing operations. 2) To be concrete, experiments were carried out aboard commercial fishing boats-bull trawlers-in the East China and Yellow Seas. There are several kinds of bull trawlers there, ranging from 50 GT to 300 GT. These bull trawlers operate throughout the year on these fishing grounds. Using a specially-devised wavemeasuring apparatus, the encountered wave heights and the motions of fishing boats were measured on board a bull trawler during fishing operations. The methods of the statistical analysis of stochastic processes were applied to the data thus obtained. 3) Measurement of wave heights (Chapter 4-1) In the study of the seakeeping qualities of a ship, it is indispensable to measure the encountered wave heights, and to obtain the relation between the motion of fishing boats and the form of ocean waves simultaneously, during the cruising course. From this point of view, the author devised a step-type wave measuring apparatus that could be mounted on a midship side of a fishing boat, and that could measure the relative encountered wave heights vertical to the sea surface at a given point of the ship\u27s body. As the observed wave heights in this study include the components of the ship\u27s motions, the true encountered wave heights were obtained by substracting the ship\u27s motions from the observed wave heights algebraically. There were some difficulties in the method of double integration of the recorded data of heaving acceleration, but the author obtained a practically effective method. The error of measurements of the wave heights by this method was estimated to be less than 10% in the range of frequency for the heaving motions of the fishing boat by the experimental way. 4) The wave characteristics of the fishing ground on the East China and Yellow Seas (Chapter 4-2) From the relationship between the wave periods and its height observed in this study, it became clear that on this fishing ground both the wave height and the wave steepness were larger in winter than in autumn. The empirical equation was obtained as follows: Ts=3.29√H₁/₃ where Ts: Wave periods obtained by the zero-crossing method. H₁/₃: Significant wave height. The wave spectra in both seas were approximately similar to the spectra of the modified Pierson-Moskowitz or the I. S. S. C. wave spectra, giving the following numerical spectrum model of the wave as below: S(ω)=0.14H²₁/₃ω₁⁻¹(ω/ω)⁻⁵exp{-0.57(ω/ω₁)⁻⁴} where ω₁=2π/Ts. 5) Short-term maximum distributions of wave heights and the motions of fishing boats (Chapter 5-2) In general the statistical distribution of data is difficult to determine, but when the process has a narrow frequency spectrum, the data are distributed according to the Rayleigh distribution. The distributions of the observed data were considered to be coincident with the theoretical distribution, and these relations were also affirmed by x² test. As for these statistics, the ratios between each average of maxima and the theoretical standard deviations that were calculated by the Gaussian distribution, respectively, were shown as estimated coefficients of maxima. The linear regression equations were obtained between the significant wave heights and the significant values of the motions of fishing boats. Based on these results, it became possible to predict the maximum amplitudes of the ship\u27s response motions in short-term. 6) Long-term maximum distributions of wave heights and the motions of fishing boats (Chapter 5-2) According to order statistics, the root mean squares of maxima on the record of each cruise were statistically analysed. The distributions of wave heights and heaving motions fitted well the logarithmic-normal and Weibull distribution functions, while the rolling and pitching motions fitted well the Weibull distribution functions. By considering the above results, the probabilities of occurrences of maxima for both wave heights and motions of fishing boats in operations could be obtained by the joint distribution of Rayleigh and Weibull. These probabilities can be applied to the problem of the limiting value. 7) Frequency response characteristics of fishing boats at sea (Chapter 5-3) As for all the data obtained by the experiments, the power spectra were calculated by Blackman-Tukey\u27s method, with Akaike\u27s smoothing coefficients. Moerover, for each of the encountered angles between waves and fishing boats, the frequency response functions were calculated by the cross-spectrum analysis method. In this system of ship\u27s motion, input was wave heights and output was motions of fishing boats. The frequency response functions were shown as values of amplitude gain, phase shift, coherency and reliability for motions of fishing boats. The forced rolling period corresponded to the free rolling period, but as for the pitching and heaving motions, the peaks of power coincided with those in the wave spectra of their frequencies. As for the pitching and heaving motions, it can be said that fairly good estimations of frequency response functions were obtained. For example, it can be seen that the coherencies were above 0.7 and the reliabilities were below 0.3 in the frequency range from 0.25 Hz to 0.05 Hz in the heaving motions for beam and quartering seas, and that in case of pitching motions, coherencies were above 0.6 or 0.7 and the reliabilities were below 0.4 in the frequency range from 0.2Hz to 0.1Hz. Therefore when the frequency response functions were calculated by the strip theory, the so-called O. S. M., it was found that the amplitude gains in both cases were similar, especially in that of the heaving motions. The effects of fishing gear during fishing operations were not considered in the calculations by the strip theory, and it may be assumed that the difference mentioned above would be affected by them. Based on these results, pitching and heaving motions were considered to be satisfied with linear for the ship\u27s motion system. 8) Estimation of numerical spectrum model of ship\u27s motions (Chapter 6) The estimation of the motions of the fishing boats during fishing operation is the most important for the investigation of the safety and the fishing plan of the boat. The author tried to establish an empirical equation to estimate ship\u27s motion spectra, based on the ship\u27s response spectra obtained by field measurements. Then the average spectra were deduced for the rolling, pitching and heaving motions for each of the encountered angles between waves and fishing boats. The average spectra obtained by the above-mentioned method were nearly the same over the whole range of sea states experienced and all the heading angles, and these spectra were calculated by the empirical equation of the Gaussian form. The non-dimensional spectra for each motion were obtained by the least squares method, and given as follows: For rolling motion:S(ω)/(H²₁/₃/ω₁)=0.0830exp{-21.3258(ω/ω₁-0.9855)} For pitching motion: S(ω)/(H²₁/₃/ω₁)=0.0634exp{-11.8376(ω/ω1-0.9761)} For heaving motion: S(ω)/(H²₁/₃/ω1)=0.0647exp{-11.6779(ω/ω₁-0.9756)} where H₁/₃: The significant value of the motions of the fishing boats which would be deduced by the significant wave height or the r. m. s. values of wave heights. ω₁: The average circular frequency of the encountered wave to the ship in the pitching and heaving motions, and the natural frequency in the rolling motion

第59回自然災害科学総合シンポジウム (2022年度防災研究所重点推進型共同研究) 講演論文集

主催：京都大学防災研究所自然災害研究協議会; 日程：令和4年9月26日（月）13時00分～17時20分; 場所：ハイブリッド開催 オンライン：Zoom 現地会場：京都大学防災研究所（宇治キャンパス）連携研究棟 大セミナー室(301)プログラム目次科学研究費補助金・特別研究促進費による突発災害調査研究令和3年度報告トンガ海底火山噴火とそれに伴う津波の予測と災害に関する総合調査 /佐竹健治 [1]自然災害研究協議会突発災害調査報告トンガの噴火による非地震性津波に対する避難に関する調査 /有川太郎 [11]自然災害研究協議会突発災害調査報告トンガの噴火により四国沿岸で発生した漁船被害等に関する調査 /田中健路 [60]自然災害研究協議会突発災害調査報告2021年Cyclone Serojaによる東ティモールの豪雨災害について /朝位孝二 [67]自然災害研究協議会突発災害調査報告3/16福島県沖の地震で発生した地震動と建物被害の対応 /境有紀 [76]2021年度災害調査報告熱海市で発生した泥流の流動特性を考慮した土砂災害対策 /竹林洋史 [83]防災研究所共同研究・地域防災実践型共同研究漸増型巨大災害リスクに対応する地域防災体制の構築 /生田英輔 [89

小型漁船の安全操業を目的とした東京湾における波浪特性に関する研究

東京水産大学博士学位論文 平成16年度(2004) 海洋生産学 課程博士 甲第356号全文公表年月日: 2008-03-31東京水産大学200

櫓漕ぎ和船漁舟の船型調査と運動性能に関する研究

The small fishing boats “wasen”, Japanese style vessels were mainly propelled with scull or sails before the last War. Nowadays, however, the wasens are mostly equipped with an outboard engine and their wooden hulls are replaced with fiberglass-reinforced plastics (FRP). Accordingly, the wasens made of wood and their boat-building techniques are gradually disappearing from fishing villages. In this research, though wasen was left from the mainstream of the present age, I promoted to the wasens for its rationality of the hull-type and provided to them and their boat-builders to the historical and the technical rank throughout the wasen\u27s model resistance test of fundamental kinematic performance and theory for security of stability. Therefore, I visited about 200 boat-builders in Kyushu, mainly within Nagasaki Prefecture and collected over 1,000 memorandums of their boat dimensions and board drawings of hull structures from 1975 to 1985. Hull lines of wasen were redrawn from the collected data. Therefore, standing on the current state mentioned above, this study was conducted to record accurately the wasen’s structure. Also, collection of hull line records, model tests and analysis of the wasens were made to clarify its characteristics. Stasistical analysis were conducted on the principal dimentions measured from the hull lines and various characteristics were probed according to type, sea area and period of use. The procedure of clarifying the wasens of their hull-type and characteristics mentioned above were intended in the first department, “Survey of hull-type and statistical analysis for wasens”, and showed them in the second to 4th Chapter. Next, the investigation of the wasens for their rationality, kinematic performance of resistance and stability in the first department were intended in the second department, “Hull-type and its kinematic performance”, and showed them in the 5th to 7th Chapter. The general result was as follows: 1) I classified and showed their characteristics about 600 various wasens which could be read necessary dimensions according to application such as fishing boat, angling, seiner, whaling, carrier and other boat from field survey. So I showed each genus of the stem post, “Miyoshi” geometry that represented wasens and made its usage clear. 2) I measured around 25 major parts of hull dimensions and showed the hull-type changes by the period and characters of the sea area usage for angling and seiner wasens. In angling wasens became small all principal dimensions and tended constant length of stern keel, “tomogawara” to approach modern times by degrees. In seiner wasens the depth became large against for the length or width of principal dimensions to approach the modern times. The characteristic usages of sea area, in angling wasens were constructed wider for the length and high stability boat around the Goto inlands and western coast of Nagasaki prefecture, and in seiner wasens were constructed so as to be applied for the fishing ground by kind and size of net fishing. 3) Next stage, I selected and produced restoring scale-models of 22 high-speed wasens used mainly as whale chaser boat from the lines of board drawings for the tank test. For the examination, there were 6 stages with full or half load condition and 3 kinds of trims, by the head and stern about 1% extended mainly in even keel for the resistance test of the towing tank. From the tank test, I showed the dimensionless total resistance coefficient sγt for actual boat and same for 5 tonnage 5γt, mean full-load displacement the sample boat used for comparison of hull-type, that were converted from model total resistance. As a result of 5γt coefficient was 0.04 to 0.07 in low speed in Fn and near by the last hump of high-speed in Fn around 0.17 for full-load and 0.15 for half-load. 4) Therefore I tried analysis about propulsion performance of wasen through the above-mentioned resistance performance and the method of sweeping propulsion force of a “Ro” for the skill seaman. As the result of wasen’s effective horsepower was of 0.04 to 0.05ps in average and was calculated 0.06ps for the maximum in a “Ro” of the skill seaman. So I inspected and suggested the possibility of the boat speed about eight knot from historical fact for the 8 sweeping pieces whale chaser “8-cho-ro, Iki-seko-bune”. 5) I examined the stability of the 22 wasens above-mentioned, to compare with “standard of stability of a small fishing boat”. I decided the KG as the gravity center of height from the keel was 65% for depth (KG=0.65D) from the field survey, and calculated the stability from inlet angle and static stability of cross-curve calculation. As a result, I understood maximum righting lever was 12 to 28cm and restoring angle was 17 to 41.5 degrees for half-load, and same as 7 to 25cm, 11 to 31.5 degrees for full-load condition to the actual boat of wasen. The estimation of dynamical stability was calculated the examination of rolling period and result of the radius gyration from the inclining test for the representative models. From the result, the consequence that satisfied a safety level was provided and the wasens were recognized as the construction that maintained security. 6) On the other hand, I examined damping coefficient about roll decay (N coefficient) from angling and seiner representative model boat. The angling boat has comparatively greatly upper stack and apron stage of chine part. When the list seemed to be buried in water damped by one swing and N coefficient was about 0.035 of 10 degrees of inclining test. But seiner boat did not show the same characteristic, N coefficient about 0.018 same as 10 degrees of inclining test. As the result, I utilized it in application of ships stability law of next section. 7) The Japanese-style fishing boat wasen by the human power propulsion with a “Ro” was the mainstream investigated from the Meiji era to the last War in Showa had been moved in FRP boat of with outboard engine equipment in present. Therefore I examined the present situation and the stability of the small fishing boat that originated from wasen for the small size fishing boat safety level and stability law. I estimated the metacentric height of GM and displacement of the each small fishing boat from the experiment of its inclining and rolling test used by the result of radius gyration before mentioned for the trawling and long-line fishing boat at Mogi-town in Nagasaki city. The consequence that examined rationality of wasen’s hull type was as follows: 1) The principal dimensions of angling and seiner fishing wasens were clarified by period and usage of sea area. 2) The total resistance performances of selective 22 fishing wasens were clarified. 3) The propulsion performance of wasen was clarified from resistance test by towing tank and the sweeping test of a “Ro” of skill seaman. For the “8-cho-ro” whaling chaser was described the possibility of the velocity of historical fact in Edo-era. 4) The selective 22 fishing wasens were confirmed security with a small fishing boat safety level. 5) The roll damping coefficient of wasens were clarified from the still water rolling experiment using the models of angling and seiner fishing boat. 6) The security of stability and current state of the small fishing boats originated from wasens were identified

実海域における船体応答の予測に関する研究

東京商船大学博士学位論文 平成14年度(2002) 交通システム工学指導教員: 井関俊夫指導教員: 大津皓平全文公表年月日: 2011-11-22東京商船大学200

小型船舶動揺が乗船者の立位姿勢に及ぼす物理的・代謝的影響の計測に関する研究

東京電機大学201

漁業労働における海難･労災事故の分析と予防に関する研究

東京海洋大学修士学位論文 2019(2020年3月) 海洋生命資源科学 修士 第3192号指導教員:稲田博史全文公表年月日: 2020-06-22東京海洋大学201

操業中の安全確保に関する基礎的研究

東京海洋大学修士学位論文 平成23年度(2011) 海洋システム工学 第1466号指導教員: 武田誠一全文公表年月日: 2012-10-01東京海洋大学201

Research on Disaster-Resistant Community Building in the Densely Populated Residential Area ― Field Survey in Omori, Ota-ku Tokyo ―

本調査は、密集市街地における行政と地域住民との連携を通じた災害抵抗力あるコミュニティづくりの手法を検討することを目的とする。本調査では、都市災害における地域危険度の高い地域に指定された東京都大田区大森の例を用いたケース• スタディーの手法により、危険要因と減災要因を調査し分析する。本調査報告は、災害抵抗力あるコミュニティづくりにおいて、地域住民を巻き込む不断の努力が、有効な手法であるという調査結果を明らかにする。The study aims to examine methods to build disaster-resistant community through the relationship between the authorities and communities in the densely populated residential area. We survey and analyze the riskfactors and mitigating factors through case study in Omori, Ota-ku Tokyo, which is designated as high-risk area in disaster. This paper clarifies the results that the tireless efforts and persistent encouragement in involvingcommunities are effective ways to ensure and establish the disaster-resistant community.東京海洋大学大学院海洋科学系海洋政策文化学部門東京海洋大学女性研究者支援機