NGHIÊN cứu về điều KIỆN môi TRƯỜNG HÀNH hải từ góc NHÌN LIÊN QUAN tới NĂNG lực sĩ QUAN HÀNG hải

Outline of Thesis ...10 Chapter 2 Competency of Bridge Team and Single Watch and Estimation on Necessary Tasks in the Navigational Environment ...15 2.1.. Base on that discussion, it is

Luận án tiến sĩ Doctoral dissertation

NGHIÊN CỨU VỀ ĐIỀU KIỆN MÔI TRƯỜNG HÀNH HẢI TỪ GÓC NHÌN LIÊN QUAN TỚI NĂNG LỰC SĨ QUAN HÀNG HẢI STUDY ON DIFFICULTY OF NAVIGATIONAL ENVIRONMENT FROM THE VIEWPOINT OF MARINER’S COMPETENCY

Tháng Ba 2009 March 2009

Khoa đào tạo sau đại học Đại học Hải dương Đông Kinh Khóa tiến sĩ Nghiên cứu Môi trường Hàng hải Ứng dụng

Graduate School of Marine Science and Technology

Tokyo University of Marine Science and Technology

Doctoral Course of Applied Marine Environment Studies

HÀ NAM NINH

Contents

Acknowledgements .1

Abstract .3

Chapter 1 Introduction .5

1.1 Navigation Environmental Difficulty .5

1.2 Nine Elemental Technique for Safe Navigation .6

1.3 Condition of Safe Navigation .7

1.4 Ship Handling Simulator .10

1.5 Outline of Thesis .10

Chapter 2 Competency of Bridge Team and Single Watch and Estimation on Necessary Tasks in the Navigational Environment .15

2.1 Introduction on Purpose of Chapter .15

2.2 Experiments of Approaching Uraga Pilot Station .15

2.3 Tasks for Mariners in Experiments .16

2.4 Data Analysis on Competency of Bridge Team and Single Watch .17

2.4.1 Controlling Ship’s Position and Adjustment of Arrival Time at Pilot Station 19 2.4.2 Collision Avoidance .21

2.5 Summary and Reason of Analyzing Bridge Team Behaviours .23

Chapter 3 Necessity of Lookout .27

3.1 Introduction on Elemental Technique of Lookout .27

3.2 Estimated Factors on Necessity of Technique of Lookout .28

3.3 Experiments for Study of Necessary Tasks for Safe Navigation .29

3.4 Some Definitions Using in Thesis .29

3.4.1 Definition of Crossing Angle .30

3.4.2 Definition of Interval of Lookout on One Target .30

3.4.3 Definition of Time Consumption of Lookout on One Target Ship from Detection Point to Understanding Motion and Estimating Future Situation .31

3.4.4 Unit of Information, Content of Information .31

3.4.5 Method of Observation for Gathering Necessary Information .33

3.5 One Example Showing Lookout Process from Detection Point to Understanding Target Motion and Estimating Future Situation in Good Visibility .35

3.6 Time Consumption for Lookout on Target Ship from Detection until Understanding Target Motion and Estimating Future Situation under Effect of Crossing Angle .36

3.7 Interval of Lookout on Target Ship under Effect of Crossing Angle .40

3.8 Necessary Measuring Number of Units of Information in Relation with Crossing Angle .43

3.8.1 Necessary Measuring Number of “Rough Bearing” .43

3.8.2 Necessary Measuring Number of “RoughDistance” .44

3.8.3 Necessary Measuring Number of “RoughAspect” and “Ship’s Type” .45

3.8.4 Necessary Measuring Number of “Rough Crossing Angle” .46

3.8.5 Necessary Measuring Number of Bearing .46

3.8.6 Necessary Measuring Number of Distance .47

3.8.7 Necessary Measuring Number of Course or Speed or CPA or TCPA .48

3.8.8 Necessary Measuring Number of BCR or TCBR .48

3.8.9 Necessary Measuring Number of “Passing Situation” .49

3.9 One Example Showing Lookout Process from Detection Point to Understanding Target Motion and Estimating Future Situation in Poor Visibility .49

3.10 Comparing Time Consumption for Lookout from Detection Point to Understanding Target Motion between Two Cases Poor Visibility and Good Visibility .50

3.11 Interval of Lookout under Effect of Visibility .52

3.12 Necessary Measuring Number of Units of Information in Poor Visibility .54

3.12.1 Necessary Measuring Number of Bearing by Radar/ARPA in Poor Visibility .54

3.12.2 Necessary Measuring Number of Distance by Radar/ARPA in Poor Visibility .55

3.12.3 Necessary Measuring Number of “RoughCrossing Angle” or Course or Speed or CPA or TCPA by Radar/ARPA in Poor Visibility .55

3.12.4 Necessary Measuring Number of BCR or TBCR

or “Passing Situation” by Radar/ARPA in Poor Visibility .56

3.13 Summary of Lookout Tasks .56

3.13.1 Lookout in Good Visibility .57

3.13.2 Lookout in Poor Visibility .59

Chapter 4 Necessity of Positioning .61

4.1 Introduction on Elemental Technique of Positioning .61

4.2 Estimated Factors on Necessity of Technique of Positioning .62

4.3 Experiments .62

4.4 Time Consumption for one Position Fixing .63

4.5 Necessary Number of Position .63

4.5.1 Effect of “Channel Width” .64

4.5.2 Effect of “Shape of Channel” .64

4.5.3 Effect of “One Risky Target” .65

4.5.4 After Avoiding Action .66

4.5.5 Positioning after Avoidance in Concerning with Crossing Angle of Risky Target .67

4.5.6 Effect of Visibility on Necessity of Positioning .68

4.6 Summary .68

Chapter 5 Necessity of Maneuvering .73

5.1 Introduction on Elemental Technique of Maneuvering .73

5.2 Experiments .73

5.3 Tasks of Maneuvering .74

5.4 Definition of Time Consumption for Maneuvering .75

5.5 Time Consumption for Maneuvering under Effect of Channel Width .75

5.6 Time Consumption for Maneuvering under Effect of Altering Point .76

5.7 Time Consumption for Maneuvering under Effect of Visibility .77

5.8 Summary .78

Chapter 6 Necessity of Communication .81

6.1 Introduction on Elemental Technique of Communication .81

6.2 Experiments .81

6.3 Unit of Information, Content of Information .82

6.4 TCPA of Target Ship at Starting Point of VHF Communication .84

6.5 Average Time Consumption for one Unit of Information .86

6.6 Content of Communication .86

6.6.1 Information for Identifying Target Ship .86

6.6.2 Information for Identifying Own Ship .88

6.6.3 Information Exchanging between Ships .90

6.6.3.1 Number of Exchanging Units of Information under Relation with CPA .90

6.6.3.2 Number of Exchanging Units of Information under Relation with Visibility .91

6.6.3.3 Content of Exchanging Information .92

6.7 Summary .93

Chapter 7 Safe Navigation Assessment .97

7.1 Concept of Safe Navigation .97

7.2 Summary of Required Tasks under Effect of Environment .98

7.2.1 Summary of Technique of Lookout .98

7.2.2 Summary of Technique of Positioning .101

7.2.3 Summary of Technique of Maneuvering .102

7.2.4 Summary of Technique of Communication .103

7.3 Calculation of Time Allowance for Mariners on Wheelhouse .105

7.3.1 Calculating TCPA1 at the Detection of Target Ship .106

7.3.2 Determine TCPA2 at the Finishing of VHF Calling .108

7.4 Example for Assessing Safe Navigation .109

Example 7.1 .109

Example 7.2 .113

7.5 Using Standard Value for Assessing Safe Navigation .117

7.6 Some Other Studies Assessing Difficulty of Environment .117

Conclusions 119

Necessary Tasks for Technique of Lookout .119

Necessary Tasks for Technique of Positioning .122

Necessary Tasks for Technique of Maneuvering .124

Necessary Tasks for Technique of Communication .125

References .127

Abbreviations .129

Figures .131

Tables .209

Tóm tắt (Abstract in Vietnamese) .225

Acknowledgements

This doctoral thesis is submitted in conformation to the requirements for the degree of Doctor

of Engineering at Tokyo University of Marine Science and Technology (TUMSAT), Tokyo, Japan and is based on research done during the Doctoral Course of Applied Marine Environmental Studies in the period of April 2006 through March 2009

First and foremost, my sincere thanks must be expressed to my supervisor, Professor KOBAYASHI Hiroaki, at the Ship Simulation Laboratory, Faculty of Marine Technology, TUMSAT for encouraging me to start this research, for his enthusiastic supervision during my doctoral work as well as his assistance in my life in Japan His patience in understanding me motivates my inspiration for the work at hand

My gratitude is expressed to my advisors, Associate Professor ISHIBASHI Atsushi and Associate Professor UCHINO Akiko, at the same laboratory of TUMSAT, for their interesting discussions and assistance during my doctoral work

My sincere thanks are expressed to my advisors, Professor ISEKI Toshio, Professor IWASAKA Naoto, Professor HAGIWARA Hideki, Professor KAKIHARA Toshiharu, at the same faculty of TUMSAT, for their discussion on my research work during doctoral course

I would like to express my sincere thanks to every staffs of Ship’s Maneuvering Simulation Center of TUMSAT for their assistance during the experiments performance in my study works

I would like to express my sincere thanks to experienced mariners from Japanese shipping companies, especially the mariners from K-line shipping company, for their joining as subjects in series of experiments in my study works

Furthermore, my deepest gratitude is expressed to Monbukagakusho (Ministry of Education, Culture, Sports, Science and Technology, Japanese Government) for scholarship support during my whole graduate course in the period of October 2005 through March 2009 and for offering me a very good chance to understand Japan and its people as well as the Japanese culture

Finally, it is impossible for me to mention everyone who has contributed with ideas, suggestions, who has assisted me in the completion of my work However, I would like to express my deep thanks to all of them

Tokyo on March 9, 2009

HÀ Nam-Ninh

Abstract

The shipping industry keeps the important role in cargoes transportation all over the world The quantity of cargoes transported by sea going vessel is very big percentage in total cargoes transportation by all mean The traffic over the sea also becomes complicated The marine accident is also happen every day It is mentioned frequently that over 80% of causes of accident are human factors Then safety of navigation in concerning with human factor is one

of most consideration from any shipping companies, maritime training centers, maritime universities and marine country governments

It is discussed and considered that safety of navigation cannot be achieved if the necessary condition is not satisfied In many studies of human factors for safe navigation, the human behaviour is analyzed in concerning with many elements of “navigation environmental difficulty” Also, the “condition of safe navigation" is recognized as the balance between the

“mariner’s competency” and “navigation environmental difficulty”

IMO, in one effort to enhance the safe navigation, proposed the STCW95 code for training the human in maritime field With the effort of proposing STCW95, IMO intends to qualify the mariners’ competency to the standard level The functional approaches mentioned by IMO are effective and important However, the understanding of STCW is different between countries and training centers Therefore the mariner’s training and assessing systems are different between countries and training centers It makes the difference in quality of mariners and different behaviour of mariners In the paper “Use of Simulator in Assessment, Learning and Teaching of Mariners” [1], the “nine elemental technique for safe navigation” was developed for assessing the mariners’ competency

However, at the present time, it is difficult to define the concrete level of “navigation environmental difficulty” that exceeds the mariners’ competency It is considered that it is possible to recognize the condition of “safe navigation” by comparing quantitatively the

“mariner competency” with “navigation environmental difficulty” Then it is necessary to define “mariners’ competency” and “navigation environmental difficulty” quantitatively

The author tried to analyze the “navigation environmental difficulty” quantitatively in concerning with mariners’ behaviour The results of the study show the relationship between

“mariners’ competency” and “navigation environmental difficulty” And those results will be expressed in this thesis

3.4.4 Unit of Information, Content of Information .31

3.4.5 Method of Observation for Gathering Necessary Information .33

3.5 One Example Showing Lookout Process from Detection Point to Understanding Target Motion and Estimating Future Situation in Good Visibility .35

3.6 Time Consumption for Lookout on Target Ship from Detection until Understanding Target Motion and Estimating Future Situation under Effect of Crossing Angle .36

3.7 Interval of Lookout on Target Ship under Effect of Crossing Angle .40

3.8 Necessary Measuring Number of Units of Information in Relation with Crossing Angle .43

3.8.1 Necessary Measuring Number of “Rough Bearing” .43

3.8.2 Necessary Measuring Number of “RoughDistance” .44

3.8.3 Necessary Measuring Number of “RoughAspect” and “Ship’s Type” .45

3.8.4 Necessary Measuring Number of “Rough Crossing Angle” .46

3.8.5 Necessary Measuring Number of Bearing .46

3.8.6 Necessary Measuring Number of Distance .47

3.8.7 Necessary Measuring Number of Course or Speed or CPA or TCPA .48

3.8.8 Necessary Measuring Number of BCR or TCBR .48

3.8.9 Necessary Measuring Number of “Passing Situation” .49

3.9 One Example Showing Lookout Process from Detection Point to Understanding Target Motion and Estimating Future Situation in Poor Visibility .49

3.10 Comparing Time Consumption for Lookout from Detection Point to Understanding Target Motion between Two Cases Poor Visibility and Good Visibility .50

3.11 Interval of Lookout under Effect of Visibility .52

3.12 Necessary Measuring Number of Units of Information in Poor Visibility .54

3.12.1 Necessary Measuring Number of Bearing by Radar/ARPA in Poor Visibility .54

3.12.2 Necessary Measuring Number of Distance by Radar/ARPA in Poor Visibility .55

3.12.3 Necessary Measuring Number of “RoughCrossing Angle” or Course or Speed or CPA or TCPA by Radar/ARPA in Poor Visibility .55

3.12.4 Necessary Measuring Number of BCR or TBCR

or “Passing Situation” by Radar/ARPA in Poor Visibility .56

3.13 Summary of Lookout Tasks .56

3.13.1 Lookout in Good Visibility .57

3.13.2 Lookout in Poor Visibility .59

Chapter 4 Necessity of Positioning .61

4.1 Introduction on Elemental Technique of Positioning .61

4.2 Estimated Factors on Necessity of Technique of Positioning .62

4.3 Experiments .62

4.4 Time Consumption for one Position Fixing .63

4.5 Necessary Number of Position .63

4.5.1 Effect of “Channel Width” .64

4.5.2 Effect of “Shape of Channel” .64

4.5.3 Effect of “One Risky Target” .65

4.5.4 After Avoiding Action .66

4.5.5 Positioning after Avoidance in Concerning with Crossing Angle of Risky Target .67

4.5.6 Effect of Visibility on Necessity of Positioning .68

4.6 Summary .68

Chapter 5 Necessity of Maneuvering .73

5.1 Introduction on Elemental Technique of Maneuvering .73

5.2 Experiments .73

5.3 Tasks of Maneuvering .74

5.4 Definition of Time Consumption for Maneuvering .75

5.5 Time Consumption for Maneuvering under Effect of Channel Width .75

5.6 Time Consumption for Maneuvering under Effect of Altering Point .76

5.7 Time Consumption for Maneuvering under Effect of Visibility .77

5.8 Summary .78

Chapter 6 Necessity of Communication .81

6.1 Introduction on Elemental Technique of Communication .81

6.2 Experiments .81

6.3 Unit of Information, Content of Information .82

6.4 TCPA of Target Ship at Starting Point of VHF Communication .84

6.5 Average Time Consumption for one Unit of Information .86

6.6 Content of Communication .86

6.6.1 Information for Identifying Target Ship .86

6.6.2 Information for Identifying Own Ship .88

6.6.3 Information Exchanging between Ships .90

6.6.3.1 Number of Exchanging Units of Information under Relation with CPA .90

6.6.3.2 Number of Exchanging Units of Information under Relation with Visibility .91

6.6.3.3 Content of Exchanging Information .92

6.7 Summary .93

Chapter 7 Safe Navigation Assessment .97

7.1 Concept of Safe Navigation .97

7.2 Summary of Required Tasks under Effect of Environment .98

7.2.1 Summary of Technique of Lookout .98

7.2.2 Summary of Technique of Positioning .101

7.2.3 Summary of Technique of Maneuvering .102

7.2.4 Summary of Technique of Communication .103

7.3 Calculation of Time Allowance for Mariners on Wheelhouse .105

7.3.1 Calculating TCPA1 at the Detection of Target Ship .106

7.3.2 Determine TCPA2 at the Finishing of VHF Calling .108

7.4 Example for Assessing Safe Navigation .109

Example 7.1 .109

Example 7.2 .113

7.5 Using Standard Value for Assessing Safe Navigation .117

7.6 Some Other Studies Assessing Difficulty of Environment .117

Conclusions 119

Necessary Tasks for Technique of Lookout .119

Necessary Tasks for Technique of Positioning .122

Necessary Tasks for Technique of Maneuvering .124

Necessary Tasks for Technique of Communication .125

References .127

Abbreviations .129

Figures .131

Tables .209

Tóm tắt (Abstract in Vietnamese) .225

Chapter 1 Introduction

1.1 Navigation Environmental Difficulty

In many previous studies carried out by Professor KOBAYASHI Hiroaki and his students, the condition of safe navigation was discussed as the balance between the required ability by environmental difficulty and mariner’s competency It is natural understanding that it is necessary to confirm the level of environmental difficulty quantitatively for comparing the tasks required by environment and tasks achieved by mariner’s competency Base on this discussion, under the supervision of Professor KOBAYASHI Hiroaki, the author carry out the

“Study on Difficulty of Navigational Environment from the View Point of Mariner’s Competency”

As the title of this thesis “Study on Difficulty of Navigational Environment from the View Point of Mariner’s Competency”, the three main items are introduced step-by-step and analyzed again and again in this thesis The first main item is “difficulty of navigational environment” The second one is the “mariner’s competency” assessed in “nine elemental technique” The third one is the “condition of safe navigation” in concerning with “difficulty

of navigational environment” and “mariner’s competency”

In the paper “The Balance Between Mariner’s Ability and Occurrence of Maritime Accidents” [2], it is considered that the condition of safe navigation is depended on the relation between mariners’ function and navigation environmental difficulty

Firstly, the “difficulty of navigational environment” is discussed and it is mainly decided by following items:

- Manoeuvering characteristic of own vessel

- Water area for navigation

- Weather and sea state

- Traffic condition

- Condition of navigational regulation

The condition of “own ship’s manoeuvering characteristic” is almost constant in comparing with others factors of “difficulty of navigational environment” in any situation of navigation

In practical maritime activities, the mariners have to understand their own ship’s maneuverability in advance And they can perform the proper handling corresponding to the manoeuvering characteristic of own vessel

On the other hand the factors mention above may variously change The level of “difficulty of navigational environment” can be changed because of changing of relating factors condition

The weather condition changes by time The traffic density and traffic condition change by time The navigation area changes from wider area to narrower area and so on

Any changing of navigation environmental condition will make the change of that difficulty and affect on the mariners’ behaviour It is considered that for accomplishing the safe navigation it is necessary to study about the “difficulty of navigational environment” from the viewpoint of “mariner’s competency”

1.2 Nine Elemental Technique for Safe Navigation

In the paper “Use of Simulator in Assessment, Learning and Teaching of Mariners” [1], the

“safe navigation" is decided by the condition of balance between the mariner’s competency and “navigation environmental difficulty” For assessing the mariners’ condition of safe navigation, many researches had been carried out in the Ship Manoeuvering Simulation Laboratory The “Nine Elemental Technique” had been developed for training and assessing the mariners’ competency Those necessary techniques for safe navigation are called as

“Elemental Technique Development” The content of the techniques is shown in table 1.1 (page 211 to 214)

For an example of “Elemental Technique Development”, the elemental technique of lookout

is shown as:

Lookout

Definition: The technique to identify and recognize the moving targets and the fixed

targets and to gather information of direction, distance and speed and to estimate the future situation of the targets

Relating factors:

- Navigation instruments (radar, radar/ARPA, AIS, VTS)

- Visibility

- Density of maritime traffic

- Traffic condition (traffic regulation)

As the definition above, the elemental technique of lookout is contained two main functions The first function is “recognition the present situation” By any methods of lookout in any condition of navigation, the mariners have to grasp the present situation in vicinity area The mariners have to get the target movement information by visual observation, radar/ARPA observation, AIS and/or asking from VTS Referring with the navigation regulation, the mariners have to fully understand about target situation It is necessary to get target’s information as much as possible, such as kind of targets, position, course, speed etc…

The second function is “estimation the future situation” By collecting the movement information of target ship, considering to the other traffic vessel, referring the navigation regulation, the mariners have to estimate the future situation The motion of own ship, the changing motion of own ship, the interaction information such as CPA, TCPA and passing distance on heading etc… have to be taken into account

Using the detail “Elemental Technique Development” as above, the Ship Maneuvering Simulation Center (Tokyo University of Marine Science and Technology) developed the

“systematic maritime education and training” for training and assessing the mariners very efficiently

1.3 Condition of Safe Navigation

The condition of “safe navigation” was discussed and defined in the study “Human Factor for Safe Navigation” [3] The concept on the condition based on the relation between the difficulty of navigational environment and mariners’ competency that decided their behaviour

The main elements that decide the navigation environmental difficulty are introduced in section 1.1 The mariners’ competency is trained and assessed by using “Elemental Technique Development” that is introduced in section 1.2

The figure 1.1 (page 133) shows the basic concept of condition of the “safe navigation” The horizontal axis is the “required ability by navigation environmental difficulty” The vertical axis is the “mariner’s competency” The line with an incline of 45 degrees indicates the minimum requirement of safe navigation Any point on this line shows the equivalent condition of both value of “required ability by navigation environmental difficulty” and

“mariner’s competency” In normal situation, the mariner’s competency has enough value for requirement of “navigation environmental difficulty” That condition is indicated in the upper

part of the line In opposite situation, the lower zone indicates the dangerous situation, the

“mariner’s competency” is insufficient with requirement of “difficulty of navigational environment”

The figure 1.2 (page 134) shows the fluctuation of navigation safety degree in concerning with the fluctuation of the mariner’s behaviour and the level of required ability caused by navigation environmental difficulty

In normal situation, the required ability by environment and mariner’s ability are being average value The required ability by environment is displayed in figure as value E The mariner’s competency is displayed as value H This condition indicates point “A” The safe navigation is satisfied

The required ability may become higher level temporary because of changing weather condition or traffic condition That higher level is indicated as value E+ If the mariners cannot understand the changing of environment, they keep their average ability (H) This condition indicates point “B” And it shows that the safe navigation is not accomplished by

“mariners’ competency” If the mariners can raise their ability higher than average value, the situation will move to point “C” The safe navigation will be realized again On the other hand, the mariners lose their necessary tension or become low ability by fatigue That situation indicates point “D” The situation of point “D” is more dangerous than the situation of point

“B”

In order to realize the condition of safe navigation, the over goal of this study is to estimate quantitatively the “required ability by navigation environmental difficulty” It means that the purpose of study is to estimate the value E Generally speaking, qualitatively, the value E is

“required ability by navigation environmental difficulty” However, quantitatively, the value

E is indicated as necessary tasks required by navigational environment When assessing safe navigation in a specific situation, it is necessary to measure the value E as “necessary tasks”

in a specific time It is considered that each necessary task requires necessary time consumption for completing that task Base on that discussion, it is considered that the value

E can indicate the total time consumption for completing all necessary tasks required by difficulty of navigational environment

It is discussed and considered that when the ship traveling over the sea, the navigational environment give the mariners a couple of tasks The mariners have to accomplish plural tasks

to keep the safety of navigation It is estimated that the tasks mainly affected by “navigation environmental difficulty” are “lookout”, “positioning”, “maneuvering” and “communication” For confirming the necessary tasks, detail of study will be expressed in following chapters of this thesis

And it is also considered that the marines have to spend time for completing the necessary tasks required by navigational environment The time consumption for necessary tasks can be called “necessary time” for completing “necessary tasks” Base on that discussion, it is considered that “the time requirement for accomplishing necessary tasks” indicates the

“required ability by navigation environmental difficulty”

The figure 1.3 (page 135) shows the main structure of the study That figure shows the above basic concept for recognition of safe navigation At the beginning, the first consideration is

“difficulty of navigational environment” Condition of “difficulty of navigational environment” is changed by time because of changing of its elements It is considered and discussed that the mariners have to complete several necessary tasks corresponding requirement of environment for keeping safe navigation The necessary tasks are considered the “nine elemental techniques for safe navigation” (table 1.1 page 211 to 214) The technique

of planning is appeared in the preparing step for making the navigation plan The technique of emergency solving is appeared in case of emergency situation such as engine trouble, rudder trouble, gyro trouble etc… It is considered that in normal proceeding situation, environmental difficulty does not affect on technique of planning and technique of emergency solving It affects on other seven techniques that shown in figure 1.3 This group technique is called as

“necessary tasks for completing safe navigation” On other hand, mariner’s competency is the important item for assessing the condition of safe navigation Generally speaking, the knowledge and competency of mariner are satisfied as the requirement of navigational environment Because before going on board, the mariners are taught and trained in maritime academies and maritime training centers The maritime academies and maritime training centers supply the necessary knowledge of navigation and other necessary knowledge to the mariners If the mariners satisfy the graduating condition showing in STCW code, the maritime academies and maritime training centers will give the certificate of competency to mariners The certificate of competency or license certifies that the mariners’ competency satisfies the requirement of STCW code The licensed mariners are satisfied for the requirement of working on board It means that the knowledge and competency of mariner are satisfied as the requirement of difficulty of navigation environmental

In practical maritime activities, it is experienced and considered that when the ship proceeding at open sea or near the coastal area where low traffic density, the single watch ability can reach the required tasks and keep the safe navigation When the ship approaching the harbour area or congested area it is necessary to set up the bridge team The bridge team activities can achieve plural tasks By comparing “necessary tasks for completing safe navigation” and “tasks achieved by mariners”, it is possible to assess the safe navigation And

in generally, the condition of safe navigation is satisfied However, the mariner’s competency

is not unlimited Within a specific allowance of time, the mariners can achieve a limited number of tasks When the “tasks achieved by mariners” (YH) (figure 1.3 (page 135)) is

greater than “necessary tasks for completing safe navigation” (XE), the condition of safe navigation is satisfied This condition is shown in lower part of figure 1.3 On the other hand,

“tasks achieved by mariners” is smaller than “necessary tasks for completing safe navigation”, the condition of safe navigation is not satisfied

As the title of this thesis “Study on Difficulty Navigational Environment from the View Point

of Mariner’s Competency”, the “necessary tasks for completing safe navigation” are quantitatively analyzed and expressed in following chapters The results of the study showing the relation between “navigation environmental difficulty” and “mariner’s competency” also are expressed in following chapters

1.4 Ship Handling Simulator

Maritime simulators are evaluated as an effective tool for maritime training and research The ship’s handling simulator in Ship Maneuvering Simulation Center of Tokyo University of Marine Science and Technology is a full mission simulator The simulator is fitted with horizontal view 225 degrees front visual, 112.5 degrees from the heading to both side and additional two rear views There are two radar/ARPA simulators and two binocular simulators

on bridge mockup There are also chart table, VHF simulator, engine simulator, steering stand, rudder indicator, turn rate indicator, wind direction and wind force indicator, etc… on bridge mockup same as the bridge facilities on actual ship It is possible to reappear many navigation areas and many kinds of navigation areas such as open sea, coastal area, congested area etc… More than 60 target ships’ motion can be simulated during the training experiments It is possible to reappear any condition of weather and sea state such as wind, wave, current, fog, rain etc…

The advantage of simulator is to be possible to reappear any maritime practical situation that

is impossible mission on training ships Then, there are many research works about “safe navigation” have been carrying out in laboratory using simulator

1.5 Outline of Thesis

The first chapter of this thesis is “Introduction” In this chapter, the author introduce briefly about “navigation environmental difficulty” and “mariner’s competency” The relationship between them in concerning with the condition of “safe navigation” is also briefly expressed And then the purpose of the study is introduced

The title of chapter 2 is “Competency of Bridge Team and Single Watch and Estimation on Necessary Tasks in the Navigational Environment” The author carried out the study on the necessary tasks in the navigational environment There was a series of experiments carried out

in Ship Maneuvering Simulation Center of Tokyo University of Marine Science and Technology The subjects attending the experiments are experienced mariners of Japanese shipping companies They were divided into two categories, single watch and bridge team From the analyzing results, it is confirmed that there are some necessary tasks that must be done by mariners The necessary tasks are “lookout”, “positioning”, “communication”,

“maneuvering”, “instrument manipulation”, “rule of road” and “management” It is considered that the mariners have to spend time for completing the necessary tasks And the time consumption for completing “necessary tasks” can be called “necessary time to complete necessary tasks” During carrying out the study, it is recognized that the time using for the technique of “instrument manipulation”, “rule of road” and “management” is involved in the time using for other techniques “lookout”, “positioning”, “communication” and

“maneuvering” For example, in case of technique of “lookout”, when the mariners using the binocular to observe target, that is the technique of “instrument manipulation” Also in

“lookout”, the mariners have to use their knowledge of “rule of road” for estimating the future target situation Then, from the chapter 3, the necessary tasks are analyzed with the technique

of “lookout”, “positioning”, “communication” and “maneuvering” And it will be understood that when the mariners complete the tasks of “lookout”, “positioning”, “communication” and

“maneuvering”, they also complete the tasks of “instrument manipulation”, “rule of road” and

“management” Because the activities for the tasks of “instrument manipulation”, “rule of road” and “management” are involved in the tasks of “lookout”, “positioning”,

“communication” and “maneuvering” respectively as above explanation

Also from that results, it is clarified that only bridge team can accomplish the tasks of “safe navigation” in congested area It means that the bridge team’s competency can satisfies the requirement of “difficulty of navigational environment” in congested area As the results of chapter 2, it is shown that the “single watch’s competency” is not qualified to complete the requirement of “difficulty of navigational environment” in congested area It means that the

“single watch’s competency” cannot satisfy the condition of navigational environment in some congested areas When proceeding at open sea or near the coastal area where low traffic density, “single watch’s competency” can complete the requirement of navigational environment However, when entering congested area, facing with the plural tasks situation, there is not enough allowable time for mariners of single watch to complete all necessary tasks Then the mariners have to give up to complete some necessary tasks For example, in congested area, it is required that the deviation of own ship from planned course line is not exceeding 2 cables For completing that requirement, the “required tasks of positioning” is fixing position on chart every 5 minutes However, the mariner of single watch is busy due to engaged in avoiding collision tasks with risky target ship, he give up to fix the position as the requirement Then it comes to the result that the own ship making a big deviation from course line As the expresses, it is said that the “single watch’s competency” is sometime lower than

the requirement of “difficulty of navigational environment” On the other hand, as the analyzing results, it is clarified that the bridge team’s competency can satisfies the requirement of “difficulty of navigational environment” in congested area It means that the

“bridge team’s competency” can complete the requirement of “difficulty of navigational environment” in any area This is the main reason for the purpose of analyzing “bridge team’s behaviours” to get the results of necessary tasks

There are 2 reasons for necessity of analyze the “bridge team’s behaviours” to get the results

of necessary tasks The first reason is the main reason expressed above The second reason is how to recognize the activities of mariners In case of single watch, many activities progress inside mariners’ brain It is impossible for researchers to recognize that at what time the mariner understand target motion, at what time the mariner decide the method of avoidance etc… But in case of bridge team, base on the discussion among bridge team members, it is possible to observe and measure many activities of mariners That is the second reason for the purpose of analyzing “bridge team’s behaviours” to get the results of necessary tasks

Base on the two reasons expressed above, from chapter 3, for studying of “necessary tasks”, all analyzing base on the data collected from the experiments with the subject bridge teams that are organized by experienced mariners of Japanese shipping companies They are more than 30 captains who have 2 to 10 years on board experience as a captain on actual ship And there are more than 60 officers who have 5 to 15 years on board experience attended the bridge teams

The chapter 3 of the thesis is “Necessity of Lookout” As the analyzing results, the necessary tasks of technique of lookout in concerning with “navigation environmental difficulty” are clarified The relation between navigation environmental elements and necessity of lookout is expressed in detail And the “necessary tasks of lookout on target” for “understanding and estimating target ship’s motion” are also clarified

The chapter 4 of the thesis is “Necessity of Positioning” From the analyzing results, it is clarified that the technique of positioning is a function of navigation environmental factors Those factors are “channel width”, “shape of channel”, “target ship”, “target ship situation” and “visibility” The relation between navigation environmental elements and necessity of positioning is shown in some proposed formulas And it is possible to calculate the necessary task of positioning under the effect of difficulty of navigational environment

The chapter 5 of the thesis is “Necessity of Maneuvering” The results of analyzing in chapter

5 show the relation of the “necessary time for maneuvering” under the effect of the

“navigation environmental elements” The relation between “navigation environmental elements” and necessity of maneuvering is shown in some proposed formulas And it is

possible to calculate the necessary time to complete the task of maneuvering in several specific situation of navigational environment

The chapter 6 of the thesis is “Necessity of Communication” The definition of unit of information is introduced in chapter 6 The average time consumption for one unit of information is analyzed and clarified The author also analyzes the content of information exchanging between ship stations Base on the analyzing results, it is confirmed that there are some important units of information have to be exchanged between ships for mutual understanding of each ship’s activities It is also confirmed the necessary numbers of units of information have to be exchanged And from those analyzing results, it is possible to calculate the necessary time for communication

The chapter 7 of the thesis is “Safe Navigation Assessment” It is considered that in the case

of risky target ship approaching, the workload of watch keeping on the wheelhouse is increased And the necessary tasks required by “difficulty of navigational environment” are also increased The mariners have to complete more required tasks than other situations Then

it is necessary to assess the “safe navigation” in the case of risky target ship approaching For assessing the “safe navigation” it is necessary to calculate the “time allowance” from the detection point of target ship’s existence The method of calculating “time allowance” is expressed in detail The total results from chapter 3, chapter 4, chapter 5 and chapter 6 show the “necessary tasks required by navigation environmental difficulty” The “necessary time” for “necessary tasks” is also expressed in detail With a specific “time allowance” and the

“necessary time for necessary tasks” it is possible to estimate the tasks achieved by mariners’ competency By comparing the “necessary tasks required by navigational environment” and

“tasks achieved by mariners’ competency” it is possible to discuss the “safe level of navigation”

And the “Conclusion” is the end of this thesis

Chapter 2 Competency of Bridge Team and Single Watch and Estimation on Necessary Tasks in the Navigational

Environment

2.1 Introduction on Purpose of Chapter

Navigation - Promotion of the Research on Mariner’s Characteristics” [1], the safe navigation was analyzing under the viewpoint of balance between “mariner’s competency” and

“navigation environmental difficulty” However, those studies analyzed mariner’s behaviour individually single watch and bridge team Then, the author intends to compare the mariner’s competency between single watch and bridge team That is the basic concept for the study works expressing in this chapter 2

The purpose of the study expressed in this chapter is to confirm the competency of single watch and bridge team in concerning to navigational environment Base on the results of study,

it is possible to recognize the necessary of organizing the bridge team in congested area and to confirm the necessary tasks in concerning with navigational environment

For the purpose of the study the experiments are divided into two categories The category A

is conducting the ship in congested area under the bridge team watch The category B is conducting the ship in congested area under the single watch There was a series of experiments carried out in Ship Maneuvering Simulation Center of Tokyo University of Marine Science and Technology

The content of this chapter is the advance study of conference paper “Study on the Necessary Tasks in the Navigation Environment” [6]

2.2 Experiments of Approaching Uraga Pilot Station

Figure 2.1 (page 136) shows the arrangement of traffic vessels for the experiments In these experiments, the mariners, both single watch and bridge team have to conduct the ship in the same situation These experiments are arranged in the approaching area of Tokyo bay The mariners are required to conduct the vessel approaching to Uraga pilot station at required time (65 minutes after starting point) The mariners are also required to make VHF call to Uraga channel pilot and Tokyo MARTIS before 10 miles from the Uraga channel entrance for reporting information

During the time of experiment, the own ship will be encountered with several risks of collision of target #12 and target #8 Manoeuvering the ship to follow the course line under

the disturbance of current is also a mission for mariners There are some other traffic vessels made the mariner pay attention Those are vessels coming from ahead: #1, #21, #5, #29, #3 and same way following vessels: #13, #9, #2, #20, #26, #6

The researcher had to observe the mariners’ behaviour and write down in recording sheets And the mariners’ behaviour is also recorded in videotapes for later analysis if there are any things not clear The researcher analyzes recording data of mariners’ behaviour for understanding the purpose of the study

2.3 Tasks for Mariners in Experiments

As the requirements, the experiment can be divided into some periods The detail of the tasks analyzing is shown in table 2.1 (page 215) First of all, the mariners have to make the VHF calling to Uraga channel pilot and Tokyo MARTIS for reporting the position and the ETA to pilot station and ETA at Uraga channel entrance In order to complete this mission, the mariners have to carry out the task of positioning for confirming the own ship position on the chart And they have to carry out the task of communication to report the reporting items for pilot station and Tokyo MARTIS

In the next event, the coming target ship #12 from port bow will make a risk of collision The mariners have to carry out the task of lookout to understand and estimate the motion of target

#12 The technique of communication is one optional action in this case For fully mutual understanding, the mariner can make the VHF calling to risky target ship to inform the method of avoiding action In any case, the mariners have to apply the technique of the rule of the road and technique of maneuvering for avoiding collision

The next mission is altering course at waypoint For completing this mission, the mariners have to complete the tasks of positioning and manoeuvering

The second event of avoiding collision appear when the small target ship number #8 approaching from the head-on In this situation, the mariners also have to complete the elemental technique of lookout of determining the risk of collision When the mariners intend

to call target ship through the VHF, they will not get any answer And the mariners have to complete the elemental technique of rule of road and manoeuvering for avoiding collision

During the time of the experiment, there are some other traffic vessels proceeds overtaking own ship Those traffic vessels affect the mariners on lookout behaviours The mariners can make some VHF conversation to those ships or Tokyo MARTIS for confirming their information

And controlling own ship speed for adjusting required time at pilot station is one important mission To complete this mission the mariners have to carry out the tasks of elemental technique of positioning and manoeuvering

2.4 Data Analysis on Competency of Bridge Team and Single Watch

All the main analyzed data of these studies are shown in the table 2.2 and table 2.3 (page 216 and 217)

In the table 2.2, the first column shows the list of necessary techniques carried out by the mariners In this column there are four techniques listed Those are “elemental technique of lookout”, “elemental technique of positioning”, “elemental technique of communication” and

“elemental technique of maneuvering” From the second column to sixth column show the behaviour data of bridge team experiments And from the seventh column to twelfth column show the behaviour data of single watch

In the first column of table 2.2, the “elemental technique of lookout” is subdivided into 4 detail actions Those are “look-out”, “bearing”, “radar” and “binocular” The meaning of

“look-out” here is the “eye observation” on target ship or any eye observation to outside of wheelhouse The meaning of “bearing” here is the “number of measuring compass bearing”

on the target ship The meaning of “radar” here is the “number of times of radar/ARPA observation” on the target ship or any observation on radar And the meaning of “binocular” here is the “number of times of binocular observation” on target ship or any observation by binocular For example, in case of bridge team experiment “2005 May 12th”, the mariners used 35.5% of time for eye observation to the total time of experiment, 3 times bearing checking on target #12, 7 times radar/ARPA checking on target #12 and 7 times binocular observation on target #12 While in case of single watch “2005 Aug 16th”, the navigation officer used 25.1% of time for “eye observation” to the total time of experiment He checked

1 compass bearing to target #12, 3 times radar/ARPA checking on target #12 and 1 binocular observation on target #12 The bridge team experiment “2005 May 12th” carried out 3 times checking bearing to target #12, 4 times checking bearing to target #8 They carried out 7 times radar/ARPA checking on target #12, 8 times radar/ARPA checking on target #8 and 100 times radar/ARPA checking on other targets They also carried out 7 times binocular observation on target #12, 6 times binocular observation on target #8 and 20 times binocular observation on other targets

The “elemental technique of positioning” is subdivided into 2 detail actions Those are “ship’s position” and “other” The meaning of “ship’s position” is the “number of time of fixing ship position on the chart” The meaning of “other” is the “number of chart checking without fixing ship’s position” In case of bridge team experiment “2005 Jun 15th”, the mariners carried out 22 “ship’s position fixing” and 41 times “chart checking without fixing ship’s position” In case of single watch “2005 Aug 19”, the navigation officer carried out 12 “ship’s position fixing” and 10 times “chart checking without fixing position”

The “elemental technique of communication” is shown in detail of 5 items Those are “VHF communication to target #12”, “VHF contacting to target #8”, “VHF reporting to pilot”,

“VHF contacting to Tokyo MARTIS” and “VHF contacting to other ships” In case of bridge team experiment “2005 Oct 27”, the mariners carried out 1 time communication with target

#12 for informing the avoidance method, 6 times contacting to pilot for confirming information of taking pilot on board, 4 times communication with Tokyo MARTIS for reporting and asking information and 1 time contacting with other ship for mutual understanding In case of single watch “2005 Aug 25th”, the navigation officer carried out 1 time contacting to pilot and 1 time contacting to Tokyo MARTIS He did not have any chance

to call VHF to other ships because of busy due to engaged in plural tasks

The “elemental technique of manoeuvering” is shown in detail of 2 items Those are “helm order” and “engine order” In case of bridge team experiment “2005 Nov 16th”, the mariners carried out 55 orders to the helmsman and 21 orders for changing engine motion In case of single watch “2005 Oct 06th”, the navigation officer carried out 33 orders to the helmsman and 18 orders for changing engine motion

The table 2.3 (page 217) shows the results of ship manoeuvering of any experiments The first column shows the list of results of ship manoeuvering activities carried out by the mariners From the second column to sixth column show the detail data of bridge teams And from the seventh column to twelfth column show the detail data of single watch The first result is the

“max deviation” The “max deviation” here is the “maximum lateral deviation” of the own ship from planned course line, calculated in metre In case of bridge team “2005 May 12th”, the “maximum lateral deviation” of the own ship from planned course line is 541 metres In case of single watch “2005 Aug 16th”, the “maximum lateral deviation” of the own ship from planned course line is 3100.8 metres The second result is the trajectory of own ship The trajectories of own ship are shows in figure 2.2 and figure 2.3 (page 137 and 138)

The third result is the position of own ship at required time at pilot station (65 minutes after starting experiment) This result is shown in detail as five items Those are “latitude deviation”, “longitude deviation”, “distance”, “speed” and “heading” The meaning of

“latitude deviation” is the deviation of the own ship from latitude of pilot station, calculated in metre The meaning of “longitude deviation” is the deviation of the own ship from longitude

of pilot station, calculated in metre The meaning of “distance” is the deviation distance of the own ship from pilot station, calculated in metre The meaning of “speed” is the actual ship speed at the 65 minutes after starting point, calculated in knots The meaning of “heading” is the actual ship heading at the 65 minutes after starting point In case of “latitude deviation”, the minus mark “-” explains for “south”, without mark explains for “north” In case of

“longitude deviation”, the minus mark “-” explains for “west”, without mark explains for

“east” For an example, in case of bridge team “2005 Jun 15th” experiment, the own ship position located south 338.7 metres, west 101.4 metres and actual distance 353 metres to the pilot station at 65 minutes from the starting time

The two last results are the avoiding action with risky target ship number #12 and target number #8 The five items to be considered here are “bearing of target at action time”,

“distance of target at action time”, “TCPA of target at action time”, “CPA of target at action time” and “CPA of target at the TCPA equal zero” The sign “OS” in the table shows that the avoidance action was taken by owner ship The sign “TS” shows that the avoidance action was taken by target ship The sign “VHF” shows that the own ship call the target ship through the VHF transceiver The word “horn” shows that the own ship send an alert to target ship by horn The word “alter” shows that the avoidance action is altering the course The word “no action” means that the mariners did not take any action for avoiding risky situation And the word “pass” explains for the target safe passing own ship’s heading because of own ship reducing speed for adjusting arrival time

For example, in case of bridge team experiment “2005 Oct 27th”, the mariners made VHF calling when the target #12 on the bearing <008> and distance 1.9NM at the TCPA 4.5 minutes and CPA 0.2 NM And passing distance at TCPA= 0 was 0.9 NM In case of target #8, the mariners reduced the own ship speed in advance for adjusting the arrival time, then the target #8 safe passing on heading at distance 2.6 NM

The detail analyzing and discussion will be expressed in following chapters

2.4.1 Controlling Ship’s Position and Adjustment of Arrival Time at Pilot Station

As the explanation in section 2.2 about the experiment arrangement, adjusting the arrival time

at the pilot station is one of the missions It is also estimated that the task of controlling ship position will be different between bridge team and single watch Then the first analyzing is about the tasks of control the ship’s position and adjusting arrival time at pilot station

The figure 2.2 and figure 2.3 (page 137 and 138) show the trajectories of the own ship in case

of bridge team and single watch The figure 2.2 shows trajectories of the own ship under control of bridge team The figure 2.3 shows trajectories of the own ship under control of single watch In both figure 2.2 and figure 2.3, the plan course is draw in dash line black colour Own ship’s trajectory is draw in lines with other symbols The black circle symbol shows the pilot station position It is easy to realize that the ship’s trajectories under bridge team control are much more smoothly than the ones under the single watch control Further more, the figure 2.4 (page 139) shows maximum lateral deviations of own ship from the course line of experiments The horizontal axis shows the categories of watch (bridge team and single watch), the vertical axis shows the deviations in meter It is clear that every single watches make a bigger deviation than the bridge team It is discussed and considered that during the experiment, the single watch made not enough position as necessity, then the task

of controlling ship position was not good as the bridge team

The figure 2.5 (page 140) shows distances from own ship’s position to the pilot station at 65th minute (requirement time at pilot station) The horizontal axis shows the categories of watch (bridge team and single watch), the vertical axis shows the actual distance from own ship to the pilot station in meter The figure 2.6 (page 141) shows the distribution of the own ship’s position at 65th minute (requirement time at pilot station) The round symbol shows the Uraga pilot station The diamond symbols show the own ship position under bridge team control And the triangle symbols show the own ship position under single watch control From the result of both two figure 2.5 and figure 2.6, it is recognized that every single watches make a bigger deviation distance from pilot station than the ones by bridge team It is discussed and considered that the ability of single watch in position controlling is much poorer than the one

of bridge team

From the analyzing results above it is confirmed that the single watch does not accomplish the necessary tasks “position controlling” and “speed adjustment” accurately It is also confirmed that the bridge team’s competencies can accomplish the necessary tasks “position controlling” and “speed adjustment” rather accurately It is clarified that conducting the ship in the congested area, the necessary tasks of “position control” and “speed adjustment” in the elemental technique “positioning” and “manoeuvering” can be only accomplished by the bridge team’s competencies

For confirming the necessary tasks in the elemental technique of “positioning” are accomplished by the bridge team’s competency, the figure 2.7 (page 142) shows the comparison between bridge team’s behaviour and single watch’s behaviour in elemental technique “positioning” The horizontal axis shows the categories of the watch The vertical axis shows the number of position fixing on the chart Figure 2.2 and figure 2.3 show the trajectories of own ship, and it is recognized that the own ship’s trajectory under the control of single watch have a big deviation from course line Generally understanding, in order to maneuver the ship strictly following the course line, it is necessary to understand the correct own ship position For exactly understanding the own ship position it is required the necessary frequency of position on the chart The results of figure 2.7 show that in average, bridge team fix 23 positions, while single watch fix 12 positions It is calculated that the numbers of position fixed by bridge team are almost as twice as the ones by single watch These results explain the reason why the own ship’s trajectories under control of bridge team are smoother than the ones under control of single watch

Figure 2.8 (page 143) shows the relation the between the number of position required by environment difficulty and the number of position achieved by competency of mariners In the congested area, the mariner face with the plural tasks situation The mariner in single watch have not enough time to complete the tasks of positioning required by environmental difficulty

Figure 2.9 (page 144) shows the own ship’s speed at 65th minute and The horizontal axis shows the categories of the watch The vertical axis shows the own ship’s speed at 65th minute in knots As the requirement of Uraga channel pilot, the own ship has to keep speed at pilot station at required time under 5 knots As the results showing in figure 2.9 (page 144), all bridge team can keep the speed in range from 4 knots to 5 knots, while the speed by single watch are various Some single watches have the speed much over the required speed On the other hand, some other single watches pass over the pilot station and use astern engine making small speed It is clarified that the single watch did not complete the task of manoeuvering In general, the mariners have to understand the motion of ship at time, and then he can control the ship speed properly However, all of single watch cannot control ship speed properly, it means that they does not fully understand the ship motion The reason is explained from the results of figure 2.8 It is said that the technique of position is “the technique to find the ship position for understanding her position and motion” In figure 2.8,the mariner of single watch is not enough time for completing the requirement of positioning, then he does not understand fully the ship motion Maneuvering action for adjusting the own ship position is also take the time The mariner in single watch is also not enough time paying for the controlling the ship speed He is also not complete the tasks of maneuvering

Figure 2.10 (page 145) shows the relation the between the maneuvering action in controlling speed required by environment difficulty and the maneuvering action achieved by competency of mariners In the congested area, the mariner face with the plural tasks situation The mariner in single watch have not enough time to complete the tasks of maneuvering required by environmental difficulty

As above analyzing results, it is natural understanding that in congested area, the mariners face with plural tasks required by navigation environmental difficulty There is not enough allowable time for single watch to complete all tasks It means that the competency of single watch is not enough to satisfy the requirement of congested area environment On the other hand, plural members contribute bridge team Then, plural members share plural tasks It is considered that in congested area, only the competency of bridge team competency can completed the required tasks of “positioning” and “manoeuvering” by environmental difficulty

2.4.2 Collision Avoidance

In the next stage of these studies, the collision avoidance is analyzed The figure 2.11 (page 146) shows the distance from the own ship to the target ship at the action point Horizontal axis shows the categories of the watch Vertical axis shows the distance from the own ship to the target ship at the action point Base on the analyzing results of figure 2.11 and table 2.3

item “avoiding #12”, it is realized that almost bridge team make a VHF calling to the target ship #12 at the distance about 2 miles for confirming avoidance action It also confirmed that the avoidance actions done by single watch are variously and rather late

Figure 2.12 (page 147) shows the passing distance (last CPA distance between ships at TCPA=0) Horizontal axis shows the categories of the watch Vertical axis shows the last CPA distance It is recognized that the last CPA in case of bridge team is about 9 cables It is also clear that in case of single watch, because of late avoidance action, the last CPA is very short

In some cases the passing distance (last CPA distance between ship at TCPA=0) is only 1 cable

It is considered that in almost case, the bridge team can understand fully the target ship motion Then they carried out VHF contacting for exchanging the method of avoidance in time On the other hand, because of plural tasks, the single watch had not enough time to watch on target So the single watch gathered not enough moving information of target Then single watch had not fully understood the target motion yet Anyway, they had to avoid collision And the action for avoiding collision was little late It is clarified that in congested area, the necessary task of lookout for estimating target ship’s motion only can be accomplished accurately by the “bridge team’s competencies”

Figure 2.13, figure 2.14, figure 2.15, and figure 2.16 show the comparison between bridge team’s behaviour and single watch’s behaviour in elemental technique “lookout” These detail-analyzing results show that the necessary tasks in the elemental technique of “lookout” are accomplished by the bridge team’s competency

Figure 2.13 (page 148) shows the percentage of time using for eye observation to the total time of experiment The horizontal axis shows the categories of the watch The vertical axis shows the percentage of time usage for eye observation From this figure, it is recognized that bridge team use about 33.7% of time for eye observation In case of the single watch, the time for eye observation is only about 21% It is clear that it is not enough allowable time for the single watch in eye observation because many tasks have to be done

The figure 2.14 (page 149) shows number of times of measuring compass bearing to the target

#12 The horizontal axis shows the categories of the watch The vertical axis shows number of times of measuring compass bearing The average value of numbers of measuring compass bearing is 4 times In case of single watch, that value is 1 times It is confirmed that the numbers of times of bearing check by the bridge team is much greater than the ones carried out by the single watch

The figure 2.15 (page 150) shows number of times of radar/ARPA observation on target #12 The horizontal axis shows the categories of the watch The vertical axis shows number of times of radar/ARPA observation The average value of numbers of radar/ARPA observation

is 7 times In case of single watch, that value is 3 times It is confirmed that the numbers of radar/ARPA observation by the bridge team is much bigger than the ones carried out by the single watch

The figure 2.16 (page 151) shows number of times of binocular check to the target #12 The horizontal axis shows the categories of the watch The vertical axis shows number of times of binocular check The average number of times of binocular check on target by the bridge team

is 6 times In case of single watch, that value is 1 times It is also confirmed that the numbers

of times of binocular check by the bridge team are much bigger than the ones carried by the single watch

The lookout is very important task for avoiding collision Mariners carry out many method of observation on target for collecting the target moving information The mariners analyze the collected information for recognizing the target motion and estimating the future situation For the decision of avoiding collision method the technique of rule of the road is taken in their mind The best way for mutual understanding between ships is to communicate through VHF Anyway, most of process depends on the collected data of target motion The above analyzing results show that the bridge team shared the plural tasks They can collect enough data of target moving information Then they carried out safe avoiding action in time It is considered that the competency of bridge team satisfies the requirement of environmental difficulty On the other hand, because of plural tasks, the single watch had not enough allowable time to estimate the risky situation The mariner in single watch gave up to collect more information

He took avoiding action a little late Even he made a big deviation from planned course line, the small passing distance occurred

Figure 2.17 (page 152) shows the relation between the required tasks of lookout for avoiding collision in congested area and the lookout tasks achieved by mariner’s competency The competency of single watch is not enough to satisfy the condition of safe navigation The bridge team can share plural tasks by plural members Then the bridge team’s competency is much higher than the single watch’s competency And the condition of safe navigation is satisfied

2.5 Summary and Reason of Analyzing Bridge Team Behaviours

As the discussion showing in this chapter 2, it leads following issues

When carrying out the watch on wheelhouse, the mariners have to complete plural tasks as the requirement of navigational environment The necessary tasks are “lookout”,

“positioning”, “communication”, “maneuvering”, “instrument manipulation”, “rule of road” and “management” [6] It is considered that the mariners have to spend time for

completing the necessary tasks And the time consumption for completing “necessary tasks” can be called “necessary time to complete necessary tasks” During carrying out these studies,

it is recognized that the time consumption spending for the technique of “instrument manipulation”, “rule of road” and “management” is involved in the time consumption spending for other techniques “lookout”, “positioning”, “communication” and “maneuvering” Then the necessary tasks of “lookout” (chapter 3), “positioning” (chapter 4), “maneuvering” (chapter 5) and “communication” (chapter 6) are quantitatively analyzed for the purpose of research as the title “Study on Difficulty of Navigational Environment from the View Point of Mariner’s Competency”

As the analyzing results, it is clarified that in congested area, the mariners face with plural

tasks required by navigation environmental difficulty There is not enough allowable time for single watch to complete all tasks It means that the competency of single watch is not enough

to satisfy the requirement of congested area environment On the other hand, plural members contribute bridge team Then, plural members share plural tasks It is considered that in congested area, only the competency of bridge team competency can completed the required tasks of “lookout”, “positioning”, “manoeuvering” and “communication” by environmental difficulty [6]

And base on the analyzing results, it is shown that the “single watch’s competency” is not qualified to complete the requirement of “difficulty of navigational environment” in congested area It means that the “single watch’s competency” cannot satisfy the condition of navigational environment in any area When proceeding at open sea or near the coastal area where low traffic density, “single watch’s competency” can complete the requirement of navigational environment However, when entering congested area, facing with the plural tasks situation, there is not enough allowable time for mariners of single watch to complete all necessary tasks Then the mariners have to give up to complete some necessary tasks For example, in congested area, it is required that the deviation of own ship from planned course line is not exceeding 2 cables For completing that requirement, the “required tasks of positioning” is fixing position on chart every 5 minutes However, the mariner of single watch

is busy due to engaged in avoiding collision tasks with risky target ship, he give up to fix the position as the requirement Then it comes to the result that the own ship making a big deviation from course line As the expresses, it is said that the “single watch’s competency” is sometime lower than the requirement of “difficulty of navigational environment” On the other hand, as the analyzing results, it is clarified that the bridge team’s competency can satisfies the requirement of “difficulty of navigational environment” in congested area It means that the “bridge team’s competency” can complete the requirement of “difficulty of navigational environment” in any area This is the main reason for the purpose of analyzing

“bridge team’s behaviours” to get the results of necessary tasks

There are 2 reasons for necessary of analyze the “bridge team’s behaviours” to get the results

of necessary tasks The first reason is the main reason expressed above The second reason is how to recognize the activities of mariners In case of single watch, many activities progress inside mariners’ brain It is impossible for researchers recognize that at what time the mariner understand target motion, at what time the mariner decide the method of avoidance etc… But

in case of bridge team, base on the discussion among bridge team members, it is possible to measure many activities of mariners That is the second reason for the purpose of analyzing

“bridge team’s behaviours” to get the results of necessary tasks

Base on the two reasons expressed above, from the next chapter, the works of “quantitatively analyzing for studying of necessary tasks” are carried out on the experiments of bridge team

in variously congested area

Base on the study results in this chapter, it is recognized that in some cases, the difficulty of navigational environment requires plural tasks, even license mariners’ handling the ship with standard competency, the allowable time is not enough for them to complete all necessary tasks It is clarified that in some cases, the safe navigation is not satisfied even the mariners with standard competency handles the ship

Chapter 3 Necessity of Lookout

3.1 Introduction on Elemental Technique of Lookout

The task of lookout is one of the most importance techniques for safe navigation In many previous studies of professor KOBAYASHI Hiroaki and his students, the proper action for avoiding collision is mostly depended on proper process of lookout In the paper Human Factor for Safe Navigation - Promotion of the Research on Mariner’s Characteristics [3], it shows that “in order to avoid the collision, mariner has to process the information that are detection, analyzing motion of target, estimation on future situation, decision of the way to avoid and execution.” Mariner has to execute all of these tasks when he faces approaching risky target ships From that issue, the author considers to study quantitatively on the tasks of lookout And the study expressed in this chapter 3 is the quantitatively analyzing work on the mariners’ behaviours of lookout on one target ship The purpose of the study in this chapter is

to verify the necessity of lookout task for one target ship As the definition of technique of lookout in “Elemental Technique Development” showing in table 1.1 (page 211 to 214), the technique of lookout is “the technique to identify and recognize the moving targets and the fixed targets and to gather information of direction, distance and speed and to estimate the future situation of the targets”

When keeping watch on the wheelhouse, the mariners have to use any method of lookout to gather the target moving information for recognizing the motion of target and estimating the future situation However, the methods of lookout change depending on the condition of navigational environment For example, in case of good visibility, the mariners can observe the target by visual method such as eye observation, binocular observation or measuring the compass bearing to target ship When the visibility becomes poor and the distance of target is outside of visibility, the mariners have to watch the target by the echo displayed on the radar/ARPA screen From this example, it is estimated that the change of navigational environment affect on the mariners’ behaviour of lookout Then the relation between the navigation environment and the behaviour on lookout is analyzed in this chapter

The information of target ship’s moving data collected by mariners is also variously The target information such as bearing, distance, course, speed etc… should be measured and gathered for understanding the target motion What information is necessary? And how many information is needed? For the purpose of this study, the content of lookout process is analyzed in detail in concerning with the factors of environmental difficulty

As the result of studies in chapter 2 expressed in summary section 2.5, it shows that there are two reasons for studying on experienced bridge team members’ behaviours in congested water area to clarify the necessity of lookout The first reason is that the competency of bridge team can accomplish the requirement of difficulty of environment in any kinds of navigation water

area The second reason is that in case of bridge team activities, it is possible to measure many mariners’ behaviour that is impossible in single watch activities Then, the data for analyzing necessity of lookout are collected from bridge team experiments The bridge teams are organized from experienced mariners of Japanese shipping companies They are more than 30 captains who have 2 ~ 10 years on board experience as captain And there are more than 60 officers who have 5 ~ 15 years on board experience attended the bridge teams

In the first step of study in this chapter 3, the factors of navigation environmental difficulty that could make the effects on necessary tasks on lookout are estimated In the next step, a series of experiments with subjects of bridge team are carried out in Ship’s Maneuvering Simulation Center of Tokyo University of Marine Science and Technology After analyzing a lot of data the “necessity of technique lookout” relating to the factors of navigational environment is clarified

The content of this chapter is the advance study of conference paper “Study on Mariner’s Behaviour in Elemental Technique of Lookout – Study on Effect of Navigation Environment” [8]

3.2 Estimated Factors on Necessity of Technique of Lookout

As the purpose of the study in this chapter 3, the factors of navigational environment could affect on the on necessary tasks on lookout are estimated and shown in the table 3.1 (page 218) The “navigation environmental difficulty” consists of five categories Those are

“maneuvering characteristics of own vessel”, “water area for navigation”, “traffic condition”,

“weather and sea state” and “rule of road” However, there are two categories are estimated that can make some effects on bridge team behaviour on “elemental technique of lookout” Those are “weather and sea state” and “traffic condition”

In case of “traffic condition” category, many factors were considered such as “crossing angle

of target ship”, CPA, traffic density etc… However, the during studying progress of analyzing lookout tasks on one target ship, the author recognize that crossing angle of target ship is the main factor that make effect on mariners’ behaviours of lookout, while other factors does not show any tendencies Then, the factor of crossing angle of target ship is taken into analyzing works and expressed in following sections

And in case of “weather and sea state” category, the “visibility” factor is also estimated to affect on mariners’ behaviour of lookout

Table 3.1 shows two factors “crossing angle of target ship” and “visibility” as the two main factors those make effect on mariners’ behaviours And the analyzing works on those two factors are expressed in following sections of this chapter 3

3.3 Experiments for Study of Necessary Tasks for Safe Navigation

A series of experiments of bridge team was carried out in Ship’s Maneuvering Simulation Center in Tokyo University of Marine Science and Technology for measuring the “necessary tasks for safe navigation”

The subject bridge teams in experiments are required to conduct the VLCC During the experiments, they navigate safely the ship in narrow water area and congested traffic situation The mariners also encounter with some types of changing visibility

The experiments cover many factors of navigation environmental difficulty that could affect

on the “necessity of technique for safe navigation” Many data of mariners’ behaviours is collected from experiments for analyzing the necessary tasks for technique of lookout The collected data are quantitatively analyzed for calculating the effect of navigation environmental difficulty on necessity of lookout

The figure 3.1 (page 153) shows one example of experiments for measuring the mariners’ behaviour The area of Singapore Strait is used for these studies Solid circle symbol shows the own ship position The broken line from own ship position shows the standard plan route

of own ship Blank circle symbol shows the traffic target arranged in experiments Blank triangle symbol shows the risky target ship arranged in experiments At the beginning of experiment, own ship VLCC under control of experienced mariners bridge team starts to proceed eastbound from the point near the Racon D (Delta) Initial course is 104 degrees Initial speed is maneuvering full speed 12 knots The disturbance effect of current and wind is very small However, the visibility is arranged as changing variously during the navigation There are several following vessels and several opposite course ships arranged in the area Also the risky target ships are arranged during the experiments for measuring the mariners’ behaviours in many techniques under the effect of dangerous target approaching For example

in this experiment, right after passing Racon Delta, the first risky target is the small ship crossing from starboard side And the next risky situation is the fishing boats locate on the middle of fairway around the Racon TK (Takong) The mariners detect the approaching target ship and carry out collecting the target moving information Then they gather and analyze the collected data for understanding the target motion and estimating the future situation Any actions of mariners’ behaviours are analyzed for studying of necessary tasks of lookout

3.4 Some Definition Using in Thesis

In this section, there are some term using in this thesis will be explained and defined