Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights Shoji FUJIMOTO 1, Akari KONDO 2, Masaki FUCHI 1, Tsukasa KONISHI 1, Hiroyuki MATSUMOTO 3 and Tomohisa NISHIMURA 3 1 Graduate School of Maritime Sciences, Kobe University, Japan 2 NYK Line, Japan 3 Japan Coast Guard Academy, Japan Abstract The authors' previous study demonstrated that vessels which had an extremely short horizontal distance between two masthead lights, even in crossing situations, judged their own Head-on situation course by observing other vessels at night. In light of the conclusions from the previous research, this paper focuses on an analysis of a questionnaire survey for pilots, ocean-going officers, domestic officers, small boat operators and fishing boat operators. The contents of the questionnaire survey investigate 1 What length of the horizontal distance between two masthead lights are required for reducing the chances of misreading another vessel s course? 2 Do you know how to observe an extremely short horizontal distance between two masthead lights of another vessel? 3 considered feasible measures. The results suggest that 1 as the horizontal distance between two masthead lights widens, the number of people who judged another vessel s course nearly 90 degrees angle of a Crossing situation increased; 2 many people did not know how to correctly observe the vessel as it has an extremely short horizontal distance between two masthead lights at night, 3 it is important to introduce how to see vessels with extremely short horizontal distance between two masthead lights (e.g. the Japan Maritime Self-Defense Force ship, the Japan Coast Guard vessel, the marine research vessel and the heavy-lift vessel) at night to mariners in Japan and/or abroad. After a background review of this issue, this paper will analyze the data from the questionnaire results, and finally discuss conclusions and offer some suggestions for measures to correct any problems, as well as directions for future research. Keywords: Collision avoidance, Navigation lights, COLREGs, Accident analysis, Ship handling simulator 1. BACKGROUND Around 04:07 on February 19, 2008 on the high seas in N 34 degrees 31.5 minutes, E139 degrees 48.6 minutes off Nosima Saki, the Japan Maritime Self-Defense Force ship DDG(Guided Missile destroyer) ATAGO collided with the fishing boat SEITOKU MARU. In this collision case, two fishermen on the SEITOKU MARU died. The Tokyo High Court conducted a criminal trial for this collision case. The Tokyo High Court deliberated on the ATAGO incident in criminal court, and gave its judgment as follows; 1) In a crossing situation at night, it is possible that a vessel misjudged the extremely short horizontal distance between two masthead lights. Therefore, there is a possibility that the other Correspondence to Shoji Fujimoto, Graduate school of Maritime Sciences, Kobe University, 5-1-1 Fukaeminami-machi, Higashinada-ku, Kobe, Hyogo 658-0022, Japan; E-mail: shojif@maritime.kobe-u. ac.jp vessel could take unnecessary collision avoidance actions or the like. The ATAGO was in a fully predictable situation in regards to the other vessel. The ATAGO should have navigated with very close observation (sharp lookout) in order to recognize the above dangerous movement in the approaching vessel in a crossing situation. In this case, if the ATAGO had watched SEITOKU MARU s actions after the right turn, the Tokyo High Court determined that this collision case would not have occur. In fact, when the SEITOKU MARU made a radical right turn about 3 minutes before the collision, the bow of the ATAGO had collided with the port mid-ships of the SEITOKU MARU. The ATAGO judged that the SEITOKU MARU" would pass the stern of the ship, because the observation of "SEITOKU MARU s" bearing had changed to the right. Vol.2 No.1, 2017 Transactions of Navigation 1

Fujimoto, S., Kondo, A., Fuchi, M., Konishi, T., et al. On the other hand, the SEITOKU MARU judged the other vessel (ATAGO) would be coming towards the ship based on an illusion of the extremely short horizontal distance between two masthead lights. The SEITOKU MARU determined to be able to resolve the situation in approach, and decided cross the other ship course. Dr. NISHIMURA was shown how the SEITOKU MARU had taken an unnecessary collision avoidance action in a radical right turn. 2) 2. PURPOSE AND SCOPE OF THE RESEARCH In a previous study, Dr. NISHIMURA showed that There is a possibility that the other vessel misjudged due to a visual illusion of the characteristic of the extremely short horizontal distance between two masthead lights. Therefore, there is a possibility that the vessel could take unnecessary collision avoidance actions or the like. Even if it was a wide angled crossing situation, the vessel misjudged the crossing situation of a nearly head-on situation. 3) The Japan Marine Accident Prevention Association carried out experiments about the limitations of the horizontal distance between two masthead lights. They were not able to find a clear basis for the above rule. They understood that the rule of the horizontal distance between two masthead lights should be one half-length of the vessel or more, which was easy to determine for other vessels by knowing the other vessel s proceeding direction, size etc. Therefore, they had concluded that if the vessel could not satisfy the above rule, for the horizontal distance between two masthead lights, it was allowed by increasing the distance as long as it could be. 4) As demonstrated in these previous studies that analyzed crossing situations at night, vessels in situations with an extremely short horizontal distance between their two masthead lights were often judged by other vessels to be in a Crossing situation of a nearly head-on collision. On the other hand, when the horizontal distance between two masthead lights was extended as long as it could be, the other vessel s proceeding direction and size can be easily determined. However, there has been no research into how vessels can determine the actual proceeding direction of a vessel by observing the horizontal distance between two masthead lights when they are at full extension. In addition, research has not clearly shown how long the horizontal distance should be in order to prevent errors caused by this visual illusion. Therefore, using the example of the collision accident of the DDG ATAGO vs. the fishing boat SEITOKU MARU, the purpose this paper was to carry out a questionnaire survey for pilots, ocean-going officers, domestic officers, small boat operators and fishing boat operators to determine the following: 1 How long should the horizontal distance between two masthead lights be in order to reduce the misreading of another vessel s course? 2 Do you know how to correctly observe a vessel in a situation with an extremely short horizontal distance between two masthead lights? 3 feasible measures. 3. PRELIMINARY STUDIES BY ANALYTIC GEOMETRY 3.1 The characteristics of the extremely short horizontal distance between two masthead lights The provisions of paragraph 1 of Article 10 of the Act on Preventing Collision at Sea enforcement regulation stipulate that When two masthead lights are prescribed for a power-driven vessel, the horizontal distance between them shall not be less than one half of the length of the vessel but need not be more than 100 meters. 5). The length of the DDG ATAGO is about 165 meters. Therefore, the DDG ATAGO should set the rear masthead light, and the horizontal distance between the two masthead lights should be at least 82.5 meters. However, the DDG ATAGO had applied the provisions of clause 1, paragraph 1 of Article 23 of the above law enforcement regulation as a special rule 6). The DDG ATAGO had been excluded from the provisions of paragraph 1 of Article 10 of the above law enforcement regulation by the above rule. So, the horizontal distance between two masthead lights of the ATAGO had become extremely narrow. Fig.1 showed the view of ATAGO type s masthead lights and starboard side light from other ship. Fig.1 The view of ATAGO type s masthead lights and starboard side light 3.2 Lengthening the horizontal distance between the two masthead lights When a vessel observed the extremely short horizontal distance between its two masthead lights of the ATAGO at night, she was misjudged as an ordinary cargo vessel. In the above situation, the "ATAGO" type s rear masthead light position was recognized at a different position from the actual position by the other vessel. Therefore, even if it was a wide-angled crossing situation, the vessel mistook the crossing situation for a nearly head-on situation, as shown in Fig.2. We analyzed the changes of the judgment of the other vessel s proceeding direction by processing the length of the horizontal distance between the two masthead lights, as shown 2 Transactions of Navigation Vol.2 No.1, 2017

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights in Fig.3 to Fig.7. Virtual state of Ordinary Cargo Vessel Virtual sate of Ordinary Cargo Vessel Fig.2 The misreading of the Course (actual and misread horizontal distance Fig.4 The misreading of the Course (25m stretch of horizontal distance Virtual state of Ordinary Cargo Vessel Virtual state of Ordinary Cargo Vessel Fig.3 The misreading of the Course (15m stretch of horizontal distance Fig.5 The misreading of the Course (35m stretch of horizontal distance Vol.2 No.1, 2017 Transactions of Navigation 3

Fujimoto, S., Kondo, A., Fuchi, M., Konishi, T., et al. Virtual state of Ordinary Cargo Vessel 4. Survey by Questionnaire We carried out questionnaire surveys for Pilots, Ocean-going officers, Domestic officers, small boat operators and fishing boat operators from May 2015 to November 2015. 4.1 The changes of the judgment of the other vessel s proceeding direction by observation of the different horizontal distance between two masthead lights We created 6 images using the ship-handling simulator at the Kobe Maritime Center in the Graduate school of Maritime Sciences, Kobe University. To simulate the collision accident of DDG ATAGO vs. Fishing boat SEITOKU MARU, the images were created. The proviso simulator did not contain the actual vessel data. Therefore, images were created using almost the same type vessels, as outlined below: Fishing boat : length of boat 12 meters DDG : length of ship 161 meters the location and distance of two masthead lights were almost the same as ATAGO Fig.6 The misreading of the Course (45m stretch of horizontal distance Virtual state of Ordinary Cargo Vessel The positions of each vessel were as follows; Fishing boat : heading direction <214> DDG : heading direction <327> direction <193>, distance 1.51 nautical miles from the fishing boat First, we created the image of the DDG as seen from the fishing boat using the above situation, and took a screen shot. This image illustrates the original distance of the two masthead lights. Next, the distance between the two masthead lights was elongated by shifting the rear masthead light to different positions: 15m, 25m, 35m, 45m and 55m. As the result, the simulated two masthead lights distances were around 30m, 40m, 50m, 60m and 70m, as shown Fig.8 to Fig.12. The 6 images above demonstrated that When a vessel is proceeding at 12 o clock, how do you determine other vessel s proceeding direction? Respondents answered each of the above 6 images by filling in the arrow in radar plotting circle, as shown Fig.13. Fig.7 The misreading of the Course (55m stretch of horizontal distance Fig.8 The view of ATAGO type s masthead lights and starboard side light as seen from the other ship (15m stretch of horizontal distance 4 Transactions of Navigation Vol.2 No.1, 2017

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights Fig.9 The view of ATAGO type s masthead lights and starboard side light as seen from the other ship (25m stretch of horizontal distance Fig.10 The view of ATAGO type s masthead lights and starboard side light as seen from the other ship (35m stretch of horizontal distance Fig.11 The view of ATAGO type s masthead lights and starboard side light as seen from the other ship (45m stretch of horizontal distance Fig.12 The view of ATAGO type s masthead lights and starboard side light as seen from the other ship (55m stretch of horizontal distance 4.2 The characteristics of the extremely short horizontal distance between two masthead lights At the end of the questionnaire, participants were shown the simulated images viewing the DDG from the fishing boat, and asked Do you know how to see a vessel with an extremely short horizontal distance between its two masthead lights? Respondents answered the above question for two scenarios. Fishing boat : the length of boat 12 meters DDG : the length of ship 161 meters the location and distance of two masthead lights almost same ATAGO The position of each vessel was as follows; Fishing boat : heading direction <214> DDG : heading direction <327> direction <193>, distance 1.51, 1.18, 0.84, 0.50 and 0.14 nautical miles from the fishing boat 5. Results and discussion The questionnaire survey was administered to 39 pilots (license renewal trainees), 33 ocean-going officers, 18 domestic officers, 170 small boat operators (license renewal trainees), 145 fishing boat operators (18 license renewal trainees), 8 Senshu Osaka bay, 3 Kagoshima, 40 Kanmon Strait, 76 Yamaguchi Prefecture, for a, total of 408 participants. 5.1 Personal data Table 1 The age of respondents Pilot Oceangoing Domestic Small Fishing boat boat Less than 20 0 0 0 0 0 20 29 0 5 5 5 1 30 39 2 16 1 11 14 40 49 0 10 5 41 20 50 59 2 1 2 60 64 9 1 1 108 112 Over 65 26 0 4 N/A 0 0 0 5 1 Total 39 33 18 170 148 Table 2 Total years of sea experience Pilot Oceangoing Domestic Small Fishing boat boat Less than 5 9 10 5 48 1 5 9 8 16 3 10 3 10 14 12 4 1 22 13 15 19 9 2 1 29 100 Over 20 1 1 8 55 28 N/A 0 0 0 6 0 Total 39 33 18 170 145 Table 3 Type of License (Pilot) First Second Third Total 37 0 2 39 Table 4 Type of License (Officer of Oceangoing vessel) First Second Third N/A Total 15 14 3 1 33 Table 5 Type of License (Officer of Domestic vessel) Third Fourth Fifth Sixth N/A Total 5 7 3 2 1 18 Vol.2 No.1, 2017 Transactions of Navigation 5

Fujimoto, S., Kondo, A., Fuchi, M., Konishi, T., et al. Table 6 Type of License (Small boat operator) First Second Personal water craft N/A Total 24 136 1 9 170 Table 7 Type of License (Fishing boat operator) First Second Personal water craft N/A Total 110 35 1 2 148 Table 8 Operation time (Small boat operator) Early morning 21 Early morning + forenoon 3 Early morning + forenoon +afternoon 2 Early morning + sunset to sunrise 0 Forenoon 75 Forenoon + afternoon 6 Forenoon + sunset to sunrise 1 Forenoon + afternoon + sunset to sunrise 0 Afternoon 15 Afternoon + Sunset to sunrise 0 Sunset to sunrise 15 All day 0 N/A 32 Total 170 Table 9 Ordinary boat uses (Multiple answers) Pleasure boat 94 Personal water craft 23 Outboard motorboat 2 Yacht 1 Paddle and/ or oar 3 Others (including unidentified boat) 16 Licensed operator who never drives 7 N/A 26 Total 172 Gill net 10 Long-line fishing 7 Set net 2 Diving 5 Picking turban and/or abalone 1 Danish seine net 4 Conger 1 Gathering sea grass and/or seaweed 2 N/A 10 Total 162 5.2 Variations of the judgment of the other vessel s proceeding direction via observation of the different horizontal distance between two masthead lights The arrows of the short hand of the watch were used to show direction. For example, the proceeding direction of 5 o clock is the arrow direction is proceeding from 11 o clock towards 5 o clock. Degrees were categorized at every 0.5 hour hand. If the arrow pointed between each hour hand, this was categorized as the closer one. Valid responses were limited to the 6 images and 2 o clock to 5.5 o clock due to measurements of the masthead light and sidelight of arc to horizon 8). As the results, each group s right answer rate on questionnaire, as shown 5.2.1 to 5.2.5, and trend line of the judgment of another vessel s course, as shown Fig.14 to Fig.18. Table 10 Operation time (Fishing boat operator) Early morning 24 Early morning + forenoon 7 Early morning + forenoon +afternoon 13 Early morning +afternoon 1 Early morning + sunset to sunrise 2 Forenoon 39 Forenoon + afternoon 9 Forenoon + sunset to sunrise 0 Forenoon + afternoon + sunset to sunrise 3 Afternoon 3 Afternoon + Sunset to sunrise 2 Sunset to sunrise 25 All day 15 N/A 5 Total 148 Table 11 Fishing methods (Multiple answers) Pole and line (bonito) fishing 101 Trawling 10 Round haul net 1 Lift net 8 Fig.13 The judgment of another vessel s course from the two masthead lights on observation 5.2.1 Pilots data Questionnaire distribution: 39 Valid responses : 34 Exceptional responses: 5 (4 unfinished answers, 1 clearly wrong answer) Effective response rate : 87.2% 5.2.2 Ocean-going officers data Questionnaire distribution: 33 Valid responses: 33 Exceptional responses: 0 Effective response rate: 100% 5.2.3 Domestic officers data Questionnaire distribution: 18 Valid responses: 15 6 Transactions of Navigation Vol.2 No.1, 2017

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights Exceptional responses: 3 (2 unfinished answers, 1 clearly wrong answer ) Effective response rate: 83.3% 5.2.4 Small boat operator s data Questionnaire distribution: 170 Valid responses: 50 Exceptional: 120 (106 unfinished answers, 14 clearly wrong answers) Effective response rate: 29.4% 5.2.5 Fishing boat operator s data Questionnaire distribution: 148 Valid responses: 84 Exceptional: 64 (45 unfinished answers, 19 clearly wrong answers) Effective response rate: 56.8% Fig.17 The Trend line of the judgment of another vessel s course via two masthead light observation (Small boat operator) Fig.18 The judgment of another vessel s course (Fishing boat operator) Fig.14 The judgment of another vessel s course (Pilot) Fig.15 The judgment of another vessel s course (Officer of Oceangoing vessel) Fig.16 The judgment of another vessel s course (Officer of Domestic vessel) 5.2.6 The overall trend The group of small boat operator's license renewal trainees actually included those who did not operate small boats, nor operate at night. The group of fishing boat operators included those who were operating only at day time, therefore they may have had little or no experience in determining the other vessel s proceeding direction and size by observation of the other vessel s navigational lights. Therefore, there were many persons who did not answer all of the questions and clearly marked wrong answers. Furthermore, there were many participants who did not finish all of the questions due to the set up the other question of navigational questions. Data analysis indicates that the most common answer of all groups was from 3 o clock to 5 0 clock. In other words, as the horizontal distance between the two masthead lights was stretched, the vessel s proceeding direction seemed to change from a nearly head-on crossing situation to a close to beam crossing situation by the other vessel. Next, we focused on persons who had the correct answer for all 6 images, and analyzed the trends of respondents who answered from 2 o clock to 4 o clock. As the result, when the rear masthead light shifted more than 25 meters, the percentage of respondents who answered from 2 o clock to 4 o clock changed greatly. When the rear masthead light shifted more than 45 meters, the percentage of respondents who answered from 2 o clock to 4 o clock was over 80%. Vol.2 No.1, 2017 Transactions of Navigation 7

Fujimoto, S., Kondo, A., Fuchi, M., Konishi, T., et al. Fig.19 The ratio of person who answers another vessel s course from 4 o clock to 2 o clock 5.3 The characteristics of the navigational lights view of the Japan Maritime Self-Defense Force ATAGO type ships The persons who knew the characteristics of the navigational lights view of the Japan Maritime Self-Defense Force ship for the first time were 189 persons 70.5% (46.3% of total respondents) in 268 persons (65.7% of total responds) expect person who did not answer. The respondents were operating various types of vessels off the Japanese coast. The above results indicate that they would not be aware of the possibility of the visual illusion causing the other vessel to misjudge the vessel's course. In addition, we focused on persons who operated boats at nighttime within the small boat operator and fishing boat operator groups. Table 12 Operation time (Fishing boat operator) all right wrong answers answer Total Person who engage in night work 29 8 37 Person who engage in day work 54 11 65 N/A 1 1 2 Total 84 20 104 Table 13 Operation time (Small boat operator) all right wrong answers answer Total Person who engage in night work 6 0 6 Person who engage in day work 32 12 44 N/A 12 2 14 Total 50 14 64 As the result, when the rear masthead light shifted more than 25 meters, the percentage of small boat operators who answered from 2 o clock to 4 o clock was 100%. On the other hand, the percentage of fishing boat operators had decreased. Fig.20 The ratio of respondents who answered from 4 o clock to 2 o clock (only fishing boat operator and small boat operators engaged in night work) Fig. 21 The ratio of respondents The people who knew the characteristics of the navigational lights view of the Japan Maritime Self-Defense Force ship for the first time were broken down into groups, as shown below; The group of pilots 40.0% (10 in 25) The group of ocean-going officers 57.8% (19 in 37) The group of domestic officers 52.9% ( 9 in 17) The group of small boat operators 93.9% (74 in 82) The group of fishing boat operators 67.0% (77 in 115) The number small boat operators was very high; the reason might be that small boat operators may not have been operating more than a few times since receiving their license. Furthermore, in the license renewal Training, they had indicated that they would not operate boats at nighttime if possible. Next, in all groups with respondents who had the correct answer for all 6 images, there were 120 out of 216 people who knew the characteristics of the navigational lights view of the Japan Maritime Self-Defense Force ship for the first time (120 persons 55.6% [29.4% of total respondents) out of 216 persons [52.9% of total responses)]. The percentages of valid responses were: The group of pilots 33.3% (7 in 21) The group of ocean-going officers 57.8% (19 in 32) The group of domestic officers 42.9% ( 6 in 14) The group of small boat operators 90.9% (40 in 44) The group of fishing boat operators 57.1% (48 in 78) 8 Transactions of Navigation Vol.2 No.1, 2017

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights worker N/A 1 0 0 1 Night person who worker 2 6 0 8 wrong Day answer worker 2 8 1 11 N/A 0 1 0 1 Total 34 63 7 104 Fig. 22 The ratio of respondents (the correct answer for all 6 images) Additional analysis focused on the group of small boat operators and the group of fishing boat operators. In the group of small boat operators who had the correct answer for all 6 images, the respondents who knew the characteristics of the navigational lights view of the Japan Maritime Self-Defense Force ship for the first time was 81.3% (26 in 32) for the daytime operators, and 83.3% (5 in 6) for the nighttime operators. There was no significant difference in the operation time of the small boat operators. Table 16 The numbers of respondents (only all right answer, small boat operators) Know Did not know N/A Total Night person who worker 1 5 0 6 all right Day answer worker 3 26 3 32 N/A 0 9 3 12 Night person who worker 0 0 0 0 wrong Day answer worker 2 10 0 12 N/A 0 2 0 2 Total 6 52 6 64 On the other hand, as was expected, the daytime operator group was more than 1.8 times the size of the nighttime operator group. We analyzed the group of fishing boat operators who had the correct answer for all 6 images. The results indicated that of those who knew the characteristics of the navigational lights view of the Japan Maritime Self-Defense Force ship for the first time, the group of daytime operators was 70.4% (38 in 54), and the group of nighttime operators was 34.5% (10 in 29). Table 17 The numbers of respondents (only all right answer, fishing boat operator) Know Did not know N/A Total person who Night all right worker 17 10 2 29 answer Day 12 38 4 54 6. CONCLUSION 6.1 The measures against mistaken illusions 6.1.1 Setting up the front masthead light at bow flagpole Vessels engaged in special missions such as ATAGO fell under a special rule 9) due to her rear structure (helicopter deck, etc.). In order to prevent similar collisions from happening in the future, measures to shift the fore masthead light at the bow flagpole. The ATAGO type vessel sets its flagpole at the bow of hull. The head of the bow flagpole position is lower than the original fore masthead light position. However, the horizontal distance between the two masthead lights was enough; around 51 meters moving forward from the original position. The horizontal distance between the two masthead lights could be stretched to around 65 meters. The Fig. 23 and Fig.24 were similar to Fig.7 and Fig.12. Data indicates that the vessel could reduce the chance of misreading the ship course by stretching the horizontal distance between the two mast head lights to around 70 meters (which shifts the rear masthead light 55 meters backwards); this was outlined in section 5.2.6. Therefore, this measure might be effective in preventing mistakes and potential collisions. It should be noted that we did not verify actually setting the fore masthead light at the bow flagpole. There was long hull length from the rear masthead light to the end of hull as shown in Fig.24. When the vessel might be recognized other vessels by observing the fore masthead light, the rear masthead light and the side light without stern light, the vessel would be collided at the rear hull of the other vessel between the rear masthead light to the end of hull. Fig.23 The view of ATAGO type s masthead lights and starboard side light from the other ship (shifted fore masthead light at bow flagpole) Vol.2 No.1, 2017 Transactions of Navigation 9

Fujimoto, S., Kondo, A., Fuchi, M., Konishi, T., et al. the proceeding direction of other vessels is done not only by visual observation, but also using navigational equipment such as RADAR. Fig.24 The misreading of the course (shifted fore masthead light at bow flagpole) 6.1.2 Making The view of the characteristic of the extremely short horizontal distance between two masthead lights universally known The view of the extremely short horizontal distance between two masthead lights (the Japan Maritime Self-Defense Force ships and the Japan coast guard vessel SHIKISHIMA ) is not widely known. In order to make this information more well known, it is necessary to make a leaflet, visual media such as DVD, and distribute them widely at the time of license renewal training. In particular, small boat operators and fishing boat operators might judge the proceeding direction of other vessels by observing the other vessel s navigational lights. Therefore, it is very important that they know the possibility of mistakes caused by visual illusions in order to prevent collisions. In addition, although the actual proceeding direction was 3.8 o clock, the pilots, ocean-going officers and domestic officers misjudged DDG s proceeding direction to be 5 o clock due to the view of the original masthead distance (14m). Therefore, it is very important that the judgment of Fig.25 The misreading of the course (Japan coast guard vessel SHIKISHIMA ) 6.2 The characteristic of Navigational lights of PCC (PCTC) and Ultra Large Container vessel The horizontal distance between two masthead lights of the current type of PCC (PCTC) has been set to conform with the minimum requirements 10). To make matters worse, the horizontal distance between the two masthead lights of the current type of Ultra Large Container vessel has been set to only conform to need not be more then 100 meters. 11) For the above reasons, those vessels had wide horizontal distances between the rear masthead light and stern lights. In other words, these are vessels with long hulls from the rear masthead light to the end of hull. Therefore, the length and size of these types of vessels could easily be underestimated by other vessels. In particular, small boats could be mistaken as two vessels due to the low height of visual perception. For 10 Transactions of Navigation Vol.2 No.1, 2017

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights example, when a small boat passes between the rear masthead light and the end of hull, a collision could occur. Taking these points into concern, it is important to make universally known the characteristics of navigational lights of PCC (PCTC) and Ultra Large Container vessel in order to prevent future collisions. On the other hand, the PCC (PCTC) and Ultra large Container vessel should outfit more lights on their hull etc. in order to prevent collisions from the beam. Such lights, which cannot be mistaken for lights specified in the rules, should not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out. For example, The PCC (PCTC) should be illuminated the rear area of the rear masthead light, and the Ultra Large Container vessel should illuminate the upper deck s passage lights. Fig.26 The beam view of PCTC Fig.27 The beam view of Ultra Large Container Vessel Vol.2 No.1, 2017 Transactions of Navigation 11

Fujimoto, S., Kondo, A., Fuchi, M., Konishi, T., et al. Fig.28 The misreading of the course (PCTC) Fig.29 The misreading of the course (ULCV) 7. REFERENCE 1) Heisei 23 nen(u)judgment of No.1545, Tokyo High Court (2013.6). 2) Tomohisa NISHIMURA: Seitokumaru wa naze Aegis kan ATAGO no kanshu wo yokogiroutoshitanoka?, Captain, Vol.424, pp.55-63,japan Captain s Association. (2014.12). 3) Tomohisa NISHIMURA; A Study on Effects of the Horizontal Distance between two Masthead Lights on Lookout by Other Vessels A Case of Collision between Guided missile Destroyer ATAGO and Fishing Boat Seitokumaru -, Journal of Japan Institute of Navigation, Vol.131, pp.33-39, Japan Institute of Navigation. (2000.1) 4) The Japan Marine Accident Prevention Association; Research report of the Marine Accident prevention, The Japan Marine Accident Prevention Association(1981.3) 5) International Regulations for Preventing Collision at Sea ANNEX 1 position and technical Details of Light and Shapes, 3. Horizontal positioning and spacing of lights (a) 6) International Regulations for Preventing Collision at Sea ANNEX 1 position and technical Details of Light and Shapes, 14. Approval 7) Calculation from the defense side of the drawing ATAGO, Heisei 23 nen(u)judgment of No.1545, Tokyo High Court (2013.6). 8) The provisions of paragraph 1 to 4 of Article 21 of the Act on Preventing Collision at Sea. International Regulations for Preventing Collision at Sea Rule 21 (a),(b) and (c) 9) The provisions of paragraph 1 and 2 of Article 23 of the Act on Preventing Collision at Sea enforcement regulation 10) The provisions of paragraph 1 of Article 10 of the Act on Preventing Collision at Sea enforcement regulation, International Regulations for Preventing Collision at Sea ANNEX 1 position and technical Details of Light and Shapes, 3. Horizontal positioning and spacing of lights (a) 11) The latter part of the the provisions of paragraph 1 of Article 10 of the Act on Preventing Collision at Sea enforcement regulation, International Regulations for Preventing Collision at Sea ANNEX 1 position and technical Details of Light and Shapes, 3. Horizontal positioning and spacing of lights (a) 12 Transactions of Navigation Vol.2 No.1, 2017

Judging Vessel Courses via the Horizontal Distance Between Two Masthead Lights 8. AKNOWLEDGMENT We were grateful for the cooperation Japan marine Science, Kinki small boat school, Kobe Maritime Center, shipping companies and fishing cooperatives bestowed on us. For the questionnaire survey, we were grateful for the cooperation Prof. Hirohumi MATSUMOTO (National Fisheries University) and Prof. Masaya YUKIHIRA (Fukuoka Institute of Technology) bestowed on us. For proofreading, we were grateful for the cooperation Prof. Matthew ROOKS (Kobe University) bestowed on us. This research was supported by JSPS KAKENHI Grant Number 15K01189. Thank you for all, note in here. presently an Associate Professor of Japan Coast Guard Academy, Japan. Institute of Navigation member. Date received: March 25, 2016 Date revised: June 17, 2016 Date accepted: July 22, 2016 9. AUTHOR S BIOGRAPHY Shoji Fujimoto: he received a B.Sc. degree in Nautical Science from Kobe University of Mercantile Marine in 1991, M.A., and Ph.D. degrees in Law from Osaka University in 2003 and 2005 respectively, and holds a Master Mariner s license. He is presently an Associate Professor of Kobe University, Japan. Institute of Navigation member. Akari Kondo: she received a B.Sc. degree in Maritime Sciences from Kobe University in 2016, and is presently an Apprentice Officer at NIPPON YUSEN KABUSIKAISHA Japan. Masaki Fuchi: he received a B.Sc. degree in Nautical Science from Kobe University of Mercantile Marine in 1995, M.A. and Ph.D. degrees in Human Sciences from Osaka University in 2008 and 2011 respectively, and holds a Master Mariner s license. He is presently an Associate Professor of Kobe University, Japan. Institute of Navigation member. Tsukasa Konishi: he received a B.Sc. degree in Maritime Sciences from Kobe University in 2014, and is presently a Graduate Student of Kobe University, Japan. Institute of Navigation student member. Hiroyuki Matsumoto: he graduated with honors from Coast Guard from Japan Coast Guard Academy in 1979. He received M.A., Ph.D. degrees in management engineering from University of Tsukuba in 1983, 1998 respectively, and is presently a Professor of Japan Coast Guard Academy, Japan. Institute of Navigation member. Tomohisa Nishimura: he received a B.Sc. degree in Coast Guard from Japan Coast Guard Academy in 1997, M.Eng. from Tokyo University of Mercantile Marine in 2004, Ph.D. degree in engineering from Tokyo university of Marine Science and Technology in 2007 respectively, and is Vol.2 No.1, 2017 Transactions of Navigation 13