Japan Maritime Research Articles

Interleaving Phenomena of the North Pacific Intermediate Water in the Offshore Area of the Kuroshio

To study the intruded phenomena of North Pacific Ocean around Boso peninsular, water property distribution in the adjacent seas to Japan is studied using the hydrographic data obtained by Japan Maritime Agency and Japan Fisheries Agency from 1973 to 1996, The scattering of water type in T-5 diagram is relatively small in the Kuroshio Region. Both the envelopes of saline side and of fresh side of the scattered data points shifts gradually from saline side to fresh side as the observation Line moves from southwest to northeast. In mixed water region, the scattering of water type increases rapidly as the observation line moves north; the envelope of fresh cold side moves towards fresh cold side much faster than that of saline side. This suggests that the water does not advect along the salinity minimum layer, but the salinity minimum layer can be understood as a boundary of two different waters aligned vertically, We defined the typical water masses as the Oyashio Water and the Kuroshio Water. The water mass below the salinity minimum layer may be created by isopycnal mixing of these two water masses with a fixed mixing rate. While the water mass above the salinity minimum cannot be created simply by isopycnal mixing. The salinity minimum layer may be eroded from upper side due to active minxing processes in the surface layer, while the water of the salinity minimum layer moves gradually southward. This appears to give an explanation why the thermosteric anomaly value at salinity minimun decereases towards south.

Preassignment Examination for Personnel on Iwo Jima

The Japan Maritime Self-Defense Force (JMSDF) requires all personnel assigned to Iwo Jima to undergo a preassignment medical examination. The efficacy and benefit of this mandatory examination has not been evaluated objectively in depth. Our purpose was to review the health status of JMSDF personnel assigned to Iwo Jima and to evaluate the correlation of the preassignment medical examination to their current health status for the study period. We divided the participants into two groups. Group Y was composed of JMSDF personnel receiving a preassignment medical examination, and group N was composed of those personnel who did not receive the examination. After the annual health examination, health status was evaluated using objective criteria. We found little statistically significant difference among group Y and group N participants. However, proportionally more patients currently receiving care for or diagnosed with hypertension, hyperuricemia, or severe obesity were identified as being members of group N than group Y. We have demonstrated that the preassignment medical examination may contribute to predicting the health status of potential Iwo Jima personnel and may contribute to controlling the cost of care associated with these specific diagnoses by limiting the assignment of at-risk personnel.

Relationship between Morbidity and Body Mass Index of Mariners in the Japan Maritime Self-Defense Force Fleet Escort Force

To establish a practical weight management program for mariners in the Japan Maritime Self-Defense Force (JMSDF) Fleet Escort Force, the relationship between morbidity and body mass index (BMI) was studied. To estimate morbidity, 10 medical problems were used as indices (hyperlipidemia, hyperuricemia, diabetes mellitus, lung disease, heart disease, upper gastrointestinal tract disease, hypertension, renal disease, liver disease, and anemia). A curvilinear relationship was found between morbidity and BMI, in which a BMI of 17.5 was associated with the lowest morbidity. This curvilinear pattern was more complex than a curve reported previously for Japanese civilians. Using the present curve and aiming for a BMI of 17.5 will help in the design and implementation of a practical management program for health promotion in the JMSDF.

海難審判庁裁決録にみる日本の水先制度の問題

海難審判庁裁決録にみる日本の水先制度の問題

瀬戸内海潮流データベースと航海計画立案支援システム

There are many inland seas where have international and domestic sailing routes in the world. They have complicated lay of the land and current. We propose Support system for Saving HOurs under Way (SSHOW), that utilizes current at these inland seas. The SSHOW bears the least fuel consumption of ships. The least fuel consumption realizes the preservation of natural environment at these inland seas. In this paper, the objective sea area is the Inland Sea of Japan (ISJ). The width of ISJ is 10 to 30 miles toward North and South, and 240 miles toward East and West. The ISJ has about 3, 000 islands, which are scattered, and the current is complicated. Besides, main sailing routes exist in the ISJ. The estimation of current directions and speeds in the ISJ is generally to carry out by using the Tide Tables of Japan Maritime Safety Agency (JMSA). 13 standard points and 212 calculation points for current are prepared in the ISJ. However, they can not calculate the current velocity of optional points in the ISJ. For supplement these lack, JMSA publishes Current Figures of each water area in the ISJ. Current database was prepared by utilizing the Current Figures. The current database is made from navigational information and geographical information, and they are piled up together in the database. The SSHOW can estimate the current velocity of optional points at optioanl time in the ISJ by using the current database. When sailing route and departure time are input the SSHOW, the hours under way are calculated in accordance with the sailing route. The SSHOW recommends the optional departure time in this day for shortest hours under way. The effective of the SSHOW was confirmed by making comparison between hours under way of actual ships and output of the SSHOW.

Diver's Lung Function: Influence of Smoking Habit

Diver's Lung Function: Influence of Smoking Habit: Shinya Suzuki. Japan Maritime Self‐Defense Force Undersea Medical Center—To assess the influence of smoking habit on divers’ lung function, we measured static lung volumes, dynamic lung volumes and flows and diffusing capacity for carbon monoxide (DLco) on 71 healthy, male, JMSDF active‐duty uniformed divers (46 smokers and 25 nonsmokers). All measurements were conducted with an automated system (CHESTAC‐25V model; Chest Ltd., Tokyo, Japan). Comparison of lung functions between smokers and nonsmokers was assessed using a Mann‐Whitney rank‐sum test. Vital capacity in smokers was 120.4 ±11.3 (mean ± SD)% of the predicted value for age and height, and in nonsmokers was 119.9 ± 15.1%. In the static lung volumes there were no differences between smokers and nonsmokers. Although the forced vital capacity (FVC), the forced expired volume in the 1st second (FEV10), and the forced expiratory flow rate at 75% of FVC expired (V75) showed no difference between two groups, the peak expiratory flow rate (PEFR) in smokers was lower than that in nonsmokers (p<0.005). The forced expiratory flow rate at 25% of FVC expired (V25) showed no difference, while the DLco in smokers was worse than in nonsmokers (p<0.01). Lung Volumes of the divers in JMSDF were larger than predicted values in the general population. Judging from the ratio of the residual volume to total lung capacity, emphysematous change with aging was negative. PEFR, FEV10 and V75 depend on the ventilatory muscle strength and diameter of the large respiratory tract. To investigate the reason why only PEFR was lower in smokers than nonsmokers in this population, more data should be collected. The finding of no difference in V25 between the two groups could not indicate that smokers had emphysematous change compared to nonsmokers. The decrease in DLco with age in smokers compared to nonsmokers, however, suggested the possibility of emphysema. Considering that emphysema is a contraindication for diving, a diver should not smoke.

大型測量船「昭洋」の電気推進システム

The new hydrographic surver ship “SHOYO” with capacity of 3, 200tons, is now under construction in the Japan Maritime Safety Agency as a replacement of the old ship “SHOYO” which was constructed in 1972.This new ship is expected to be completed in March, 1998.The electric propulsion system was first employed in the Japan Meritime Safety Agency. It is equipped with diesel engine generators as a power source for every application on sailing.The electric propulsion system is provided with 2 sets of 2, 800kW main-generators to drive the fixed pitch propellers at a motor output and speed of 2, 100kW/262-290rpm ahead.The thyristor motor system is applied to driving 2 sets (2 shafts of propellers.)In addition, one set of bow-thruster (800kW) is located at the stem for controling the ship with the Joy-stick conbined to the electric propulsion system during fixed point observation.

Performance of the Patrol Icebreaker “TESHIO” in Ice-Covered Waters

The patrol icebreaker “TESHIO” was built and delivered to the Japan Maritime Safety Agency in Autumn 1995. Full-scale trials in ice were conducted at the Sea of Okhotsk in February, 1996. Several kinds of test were performed in order to confirm her performance such as continuous ice-breaking, ramming and stopping performance, turning capability and zigzag course manoeuvrability, and coordinated ice-breaking operation together with the patrol icebreaker “SOYA”.While her design and construction were in process, series of model test were carried out both in ice and in ice-free water as the joint research project between Ship Research Institute, Ministry of Transport and NKK Corporation. At the ice model basins of the two organizations, comprehensive model tests in ice were conducted which included resistance and self-propulsion tests in various ice conditions, ramming and turning tests in level ice.This paper describes the results of model and full-scale tests of “TESHIO” and their correlation for both continuous ice-breaking and ramming performance.In order to predict the required BHP for the continuous ice-breaking in level ice, the propulsion coefficient was decomposed into three parts which denote effects of open water characteristics, overload and propulsor/ice interaction, respectively. The thrust deduction coefficient obtained from towed propulsion tests in ice showed very good agreement with that from overload tests in ice-free water. The predicted BHP showed good agreement with the full-scale results when the effect of propulsor/ice interaction was taken into consideration.A prediction formula for ramming penetration distance was devised using an energy-based method. Correlation of both the model and full scale data to the prediction results showed that thrust loss due to the propulsor/ice interaction and the automatic overload protection control of the main engine had much influence on the prediction of ramming performance.

硫黄島の面積の長期変動

Iwo Jima is small volcanic island located isolate in the Western Pacific Ocean about 1, 250 km south of Tokyo. The island with the area about 23 km2 is covered with considerably dense vegetation and no rivers exist in this island. Thus, the source of sediments to nourish the beach seems to be quite limited in this island. Further, the coast is always subjected to rough seas because it is fully exposed to the open sea. Nevertheless, the coast is mostly rimmed by sandy beaches with about 200 m in width and the shoreline is still advancing toward the sea which increases the beach area year by year. Many scientists have pointed out that this increase might be caused by an unusual upheaval of this island exceeding 30 cm per year. However, no quantitative analyses have been done yet on this unique phenomenon that prevents from constructing any port facilities in this island. Thus, the author intends to investigate the features of the long-term variation of the area which have occurred in Iwo Jima during the past seven decades and to examine its variation mechanism.To investigate the features of the long-term variation, analyses are conducted on the seven maps and charts of Iwo Jima which have been published in the period from 1911 to 1981. The analysis reveals that the island has kept increasing its area over the past seven decades although the increasing rate has changed drastically in 1952 from 30, 000 m2 to 90, 000m 2 peryear and that the increased area has reached roughly 4.3 km2 in total during the sevendecades. This change of the increasing rate well corresponds to the fact that the upheaval rate of the island has changed in 1952 from roughly 10 cm to 30 cm per year which has been found by Kosaka et al. in 1979.To examine the effect of the upheaval on the features of the long-term variation of the area, calculation is carried out by giving the various values of imaginary upheaval to the bathymetric data shown on the chart covering the sea around Iwo Jima published by the Hydrographic Department of Japan Maritime Safety Agency in 1981. The result of the calculation indicates that the upheaval of 10 cm per year corresponds to the increasing rate of the beach area roughly 43, 000 m2 per year and the upheaval of 30 cm per year corresponds to the increasing rate of the beach area roughly 130, 000 m2 per year when the foreshore slope is assumed to be 1/20. These values are surely the ones before the beach is transformed by the action of the ocean waves. However, comparison of these values with the ones found through the former analyses indicates that the calculation has provided quite a reasonable estimation of the increase of the beach area. These findings clearly indicate that the continuous upheaval is the governing factor to cause the increase of the beach area in Iwo Jima.

Warm eddy movements in the eastern Japan Sea

Warm eddy movements and their areal extent in the eastern Japan Sea were described by presenting space-time diagrams for the warm eddy locations and magnitudes. The analyzed data were compiled from Japan Maritime Safety Agency thermal maps at 200 m depth from 1985 to 1992. Two to four warm eddies always existed in the eastern Japan Sea and exhibited both internnual and annual signals. We found that warm eddies were generated in spring around Oki Spur at least three times during the analyzed period of eight years, moved eastward, and interacted with neighboring warm eddies, which were involved in coalescences or separations. The warm eddy distributions off Noto Peninsula have clear seasonal preference. Warm eddies moved eastward from Noto Peninsula in winter-spring to North Japan in the next winter, with mean translation speeds of 0.5–2 cm s−1. Warm eddies reaching North Japan typically decayed during a few month after splitting into two or three mesoscale warm eddies.

Mass screening for colorectal cancer on Japan Maritime Self Defense Force in Nagasaki prefecture

Mass screening for colorectal cancer on Japan Maritime Self Defense Force in Nagasaki prefecture

HISTORICAL BUILDUP OF OIL SPILL RESPONSE CAPABILITY IN JAPAN

ABSTRACT With the large oil spill that occurred in 1971 as an impetus, Japan's Maritime Pollution and Disaster Prevention Law was amended in 1973 and subsequently in 1976. The amendments required owners of vessels and petroleum facilities to retain designated quantities of oil boom, sorbent, dispersant, and other items to minimize impact from spills. A large oil spill caused by a ruptured crude oil storage tank in 1974 led to the enactment of additional legislation: the Petroleum Complex Disaster Prevention Law. Under this, petroleum facilities are required to maintain designated quantities of oil boom, oil boom deploying vessels, skimming boats, and the like. These legislative measures, together with voluntary efforts, have contributed to a sound buildup of the nation's oil spill response force. However, the response capability including stockpiled materials and equipment has been designed primarily to cope with incidents in closed waters such as inland seas, bays, and ports, and hence not for a oil spill in open seas as large as that from the Exxon Valdez. As one of the measures under the 1990 International Convention for Oil Spill Preparedness, Response and Cooperation, the Government of Japan has entrusted the Petroleum Association of Japan with an oil spill response capability reinforcement project to cope with a large oil spill should one occur in Japanese waters or nearby seas. Under the scheme, during the 5 year period beginning in 1991, the Petroleum Association of Japan is scheduled to build up, using subsidies from the government, stockpiles of cleanup equipment and materials and to augment the existing response capability.

自動海図改補装置の試作とその評価

A new system for automatic correction of nautical charts is proposed. This system consists mainly of a X-Y plotter and a microcomputer for its control as hardware, and as software, a database to offer information for correcting charts and a system software. In the database, the information described in "Notices to Mariners" published Japan Maritime Safety Agency is arranged in the very compact form of symbols by using the hierarchy structure introduced in the classification of contents about chart correction. This compactness allows this system to become small size and, as the result, to operate usefully on board. The performance of this system is discussed in comparison with the chart correction by hand and the adaptation to actual corrections is investigated. It shows that the percentage of automation reaches 96% in all paragraphs of "Notices to Mariners".

富山トラフの変動地形と地質構造

Hydrographic Department, Japan Maritime Safety Agency conducted multichannel seismic reflection and refraction survey and Sea Beam bathymetric survey in the Toyama Trough extending northward in the southeastern margin of the Japan Sea. The purpose of the survey is to reveal the geological structure and tectonic landform of the Toyama Trough and to examine the hypothesis that the Toyama Trough is subduction zone.Seismic profiles across the Toyama Trough do not support the presence of distinct subduction zone along the trough because the basement of the trough is not traceable beneath the Sado Ridge. This suggests that the Toyama Trough is different in geological feature from typical subduction zone such as the Japan Trench or the Nankai Trough, where subducting oceanic basement is clearly traceable beneath the overriding plate in seismic profiles. Further, seismic profiles show that the sedimentary layers thicken to the east in some places and to the west in the other places. These features indicate that convergent plate boundary is not present, or only extremely incipient plate boundary is present along eastern margin of the Toyama Trough. However, the tectonic landform and geological structure characterized by the presence of active reverse faults indicate that Toyama Trough has been subjected to compressional stress.

航行用100kHz電波帯の伝搬特性の解析とそれらによる船位精度の改善…VII : デッカ・システム-II

The present paper is construced by the eight monitoring records of the Japan Maritime Safety Agency over the Kita Kyushu Decca Chain during three years (1969-1972). And the other experiments were made to assist the analysis of these results above in Kagoshima Bay. The daytime phase difference deviations of each pattern of monthly mean at monitoring sites were variable respectively, its fluctuated range was set about ±10 cel normaly, and 30 cel range or more occured sometimes in special sites. It was considered that this phenomenon might be due to the skywave contamination, because the ground constant and the refractivity of atmosphere would not affect the propagation condition in such amplitude of phase fluctuation. These monitoring sites were situated in lighthouse where standed on the top of high cliff and faced seaside generally. The author examined that making the data apply to the Decca correction table at the surface of seawater off the coast. Moreover, in this examination, the range free from the effect was observed. The field strength and phase difference were obtained inhomogeneously and unsmoothly from sea to land and from sea to mountain. The difference of Decometer reading taken between land and sea is correct when derived from propagation mode above. The error presumably reduced in accordance with the increase of the distance from the coast. The correlation between the meteorological effects and the variation of phase difference pattern was also discussed. 16 (Purple), 4 (Red) and 3 (Green) were picked up during this period for example, and the analyses were based on variation of monitoring site simultaneously over five sites. The purple pattern is the most sensitve to the front approaching and the perfect correlation was admitted. The range of the effect on the phenomenon was observed to be within 100nmi from transmitting station.