THE EFFECTIVENESS OF DYNAMIC POSITIONING IN OFFSHORE OPERATIONS

HE EFFECTIVENESS OF DYNAMIC POSITIONING IN OFFSHORE OPERATIONS

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A Dissertation Presented in Partial Fulfilment

of the Requirements for the Degree of

 

 

 

 

 

 

 

6 March 2016

 

Abstract

Dynamic positioning is very important in maritime industry as well as in the energy sector since the technology allows operators to be in control of offshore vessel against strong forces of nature like wind, current and waves while undertaking offshore operations. Objectives investigated in this study include evaluating the need for dynamic positioning in offshore operations, to review the existing publications on dynamic positioning classes, techniques and systems, to assess the benefits of dynamic positioning of the vessel in offshore operations and to examine the limitations of dynamic positioning systems. The researcher used descriptive statistical analysis where closed ended questionnaire was used for primary data collection. Sample size of 90 respondents derived from 15 marine companies using simple random sampling was used in the study. The investigator used chi-square test and descriptive statistical analysis for data analysis. The findings of this study indicate that dynamic positioning plays a very important role in controlling offshore vessels and is therefore needed in offshore operations. Benefits of dynamic positioning include the fact that dynamic positioning system is not dependent on water depth, the system saves time, dynamic positioning is not limited by obstructed seabed and that dynamic positioning system enables the operator to have full control of the vessel. Moreover, the findings of this study indicate limitations of dynamic positioning to include vulnerability of dynamic system to electronics and thrusters failure, power failure and power shortages. Dynamic positioning has high start-up cost and the system requires highly educated staff members to manage and operate.

 

 

 

 

 

Table of Contents

Abstract i

List of Tables. iv

List of Figures. vii

CHAPTER 1    –     INTRODUCTION.. 1

1.1       BACKGROUND.. 1

1.2       JUSTIFICATION.. 2

1.3       AIM.. 2

1.4       OBJECTIVES.. 2

1.5       LIMITATIONS.. 2

1.6       RESEARCH OUTLINE.. 3

1.7       SUMMARY.. 3

CHAPTER 2    –     LITERATURE REVIEW AND METHODOLOGY.. 4

2.1       INTRODUCTION.. 4

2.2       THE NEED FOR DYNAMIC POSITION SYSTEM.. 4

2.3       EXISTING PUBLICATIONS.. 5

2.4       DYNAMIC DESIGN AND CONTROL SYSTEM.. 6

2.5       CAPABILTY OF DP SYSTEM ANALYSIS.. 8

2.6       FAULTS AND SAFETY OF DYNAMIC POSITIONING SYSTEM.. 8

2.7       METHODOLOGY.. 10

2.7.1        Research design.. 10

2.7.2        Types and Sources of Data. 10

2.7.3        Participants and Sampling. 10

2.7.4        Data Collection.. 11

2.7.5        Questionnaire. 11

2.7.6        Data Analysis. 11

2.7.7        Ethical Consideration.. 12

2.8       SUMMARY.. 12

CHAPTER 3    –     DYNAMIC POSITIONING ANALYSIS.. 13

3.1       INTRODUCTION.. 13

3.2       DEMOGRAPHIC INFORMATION.. 13

3.3       DESCRIPTIVE STATISTICAL ANALYSIS.. 19

3.4       CHI-SQUARE TESTS.. 28

3.5       SUMMARY.. 33

CHAPTER 4    –     BENEFITS OF DYNAMIC POSITIONING ANALYSIS.. 34

4.1       INTRODUCTION.. 34

4.2       DESCRIPTIVE STATISTICAL ANALYSIS.. 34

4.3       CHI-SQUARE TESTS.. 46

4.4       SUMMARY.. 50

CHAPTER 5    –         EFFECTIVENESS AND LIMITATIONS OF DYNAMIC POSITIONING ANALYSIS   51

5.1       INTRODUCTION.. 51

5.2       DESCRIPTIVE STATISTICAL ANALYSIS.. 51

5.3       CHI-SQUARE TESTS.. 65

5.4       SUMMARY.. 68

CHAPTER 6    –     DISCUSSION AND ANALYSIS.. 70

6.1       INTRODUCTION.. 70

6.2       Dynamic Positioning. 70

6.3       Benefits of Dynamic Positioning. 71

6.4       Limitations and Effectiveness of Dynamic Positioning. 72

6.5       SUMMARY.. 74

CHAPTER 7    –     CONCLUSION AND REFLECTION.. 75

REFERENCES.. 77

APPENDIX A      Survey Questionnaire. 84

 

 

List of Tables

Table 3.1: Age. 13

Table 3.2: Education Level 15

Table 3.3: Gender 16

Table 3.4: Work Designation.. 17

Table 3.5: Conversance with the subject of the effectiveness of dynamic positioning in offshore operations. 18

Table 3.6: Dynamic positioning system plays an important role in offshore operations. 19

Table 3.7: Dynamic positioning enables offshore vessels to stay in position.. 20

Table 3.8: Dynamic positioning overcome changes in the location of offshore vessels. 21

Table 3.9: Dynamic positioning system prevent the impact of current, wind, wave acting on the ship  22

Table 3.10: Dynamic positioning allows greater manoeuvring flexibility. 23

Table 3.11: Dynamic positioning is advantageous compared to Jack-up barge and spread mooring to anchor pattern.. 24

Table 3.12: Dynamic positioning system is capable of reacting to weather changes. 25

Table 3.13: Dynamic positioning is able to adapt to operation requirements. 26

Table 3.14: The use of dynamic positioning system comes with less risk for environment 27

Table 3.15: Dynamic positioning system and ability of offshore vessels to stay in position.. 29

Table 3.16: Chi-Square Tests. 29

Table 3.17: Chi-Square Tests. 30

Table 3.18: Dynamic positioning system and manoeuvring flexibility. 30

Table 3.19: Dynamic positioning system and its capability to react to weather changes. 32

Table 3.20: Chi-Square Tests. 33

Table 4.1: Dynamic positioning help in increasing demand for oil and gas exploitation in deep sea  34

Table 4.2: Dynamic positioning has many important benefits in Maritime industry. 36

Table 4.3: Dynamic positioning has contributed in increasing global economic growth.. 37

Table 4.4: Dynamic positioning saves time. 38

Table 4.5: Dynamic positioning system is not dependent on water depth.. 39

Table 4.6: Dynamic positioning allows quick set up. 40

Table 4.7: Dynamic positioning is not limited by obstructed seabed. 41

Table 4.8: Dynamic positioning does not need anchor handling tugs. 42

Table 4.9: Dynamic positioning saves money through low fuel cost among other factors. 43

Table 4.10: Dynamic positioning saves money due to no expenditure on tugboats. 44

Table 4.11: Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces. 45

Table 4.12: Dynamic positioning and time saving. 46

Table 4.13: Chi-Square Tests. 47

Table 4.14: Chi-Square Tests. 47

Table 4.15: Dynamic positioning and dependence on water depth.. 48

Table 4.16: Dynamic positioning and saving money through low fuel cost 49

Table 4.17:Chi-Square Tests. 50

Table 5.1: Dynamic positioning has both effectiveness and limitations. 51

Table 5.2: Dynamic positioning enables the operator to have full control of the vessel 53

Table 5.3: Dynamic positioning system is capable of maintaining required heading automatically  54

Table 5.4: Dynamic positioning system is capable of maintaining required position automatically  55

Table 5.5: Dynamic positioning can be used in situations where a lot of precision is needed  56

Table 5.6: Dynamic positioning can be used on locations where other systems cannot be applied  57

Table 5.7: Operating dynamic positioning requires highly educated staff members. 58

Table 5.8: Dynamic positioning require position reference continuously. 59

Table 5.9: Dynamic positioning requires a lot of power and the fuel cost is high.. 60

Table 5.10: Dynamic positioning is vulnerable to electronics and thrusters failure. 61

Table 5.11: Dynamic positioning system is quite vulnerable to power failure and shortages  62

Table 5.12: Training on dynamic positioning system is quite expensive. 63

Table 5.13: Dynamic positioning has high start-up cost 64

Table 5.14: Dynamic positioning and control of offshore vessels. 66

Table 5.15: Chi-Square Tests. 66

Table 5.16: Chi-Square Tests. 67

Table 5.17: Dynamic positioning and maintaining required position automatically. 68

 

List of Figures

Figure 3.1: Age. 14

Figure 3.2: Education Level 15

Figure 3.3: Gender 16

Figure 3.4: Work Designation.. 17

Figure 3.5: Conversance with the subject of the effectiveness of dynamic positioning in offshore operations. 18

Figure 3.6: Dynamic positioning system plays an important role in offshore operations. 19

Figure 3.7: Dynamic positioning enables offshore vessels to stay in position.. 21

Figure 3.8: Dynamic positioning overcome changes in the location of offshore vessels. 22

Figure 3.9: Dynamic positioning system prevent the impact of current, wind, wave acting on the ship  23

Figure 3.10: Dynamic positioning allow greater manoeuvring flexibility. 24

Figure 3.11: Dynamic positioning is advantageous compared Jack-up barge and spread mooring to anchor pattern.. 25

Figure 3.12: Dynamic positioning system is capable of reacting to weather changes. 26

Figure 3.13: Dynamic positioning is able to adapt to operation requirements. 27

Figure 3.14: The use of dynamic positioning system comes with less risk for environment 28

Figure 4.1: Dynamic positioning help in increasing demand for oil and gas exploitation in deep sea  35

Figure 4.2: Dynamic positioning has many important benefits in Maritime industry. 36

Figure 4.3: Dynamic positioning has contributed in increasing global economic growth.. 37

Figure 4.4: Dynamic positioning saves time. 38

Figure 4.5: Dynamic positioning system is not dependent on water depth.. 39

Figure 4.6: Dynamic positioning allows quick set up. 40

Figure 4.7: Dynamic positioning is not limited by obstructed seabed. 41

Figure 4.8: Dynamic positioning does not need anchor handling tugs. 42

Figure 4.9: Dynamic positioning saves money through low fuel cost among other factors. 43

Figure 4.10: Dynamic positioning saves money due to no expenditure on tugboats. 44

Figure 4.11: Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces. 45

Figure 5.1: Dynamic positioning has both effectiveness and limitations. 52

Figure 5.2: Dynamic positioning enables the operator to have full control of the vessel 53

Figure 5.3: Dynamic positioning system is capable of maintaining required heading automatically  54

Figure 5.4: Dynamic positioning system is capable of maintaining required position automatically  56

Figure 5.5: Dynamic positioning can be used in situations where a lot of precision is needed  57

Figure 5.6: Dynamic positioning can be used on locations where other systems cannot be applied  58

Figure 5.7: Operating dynamic positioning require highly educated staff members. 59

Figure 5.8: Dynamic positioning require position reference continuously. 60

Figure 5.9: Dynamic positioning require a lot of power and the fuel cost is high.. 61

Figure 5.10: Dynamic positioning is vulnerable to electronics and thrusters failure. 62

Figure 5.11: Dynamic positioning system is quite vulnerable to power failure and shortages  63

Figure 5.12: Training on dynamic positioning system is quite expensive. 64

Figure 5.13: Dynamic positioning has high start-up cost 65

 

CHAPTER 1    –     INTRODUCTION

1.1         BACKGROUND

The purpose of the current study is to examine effectiveness of dynamic positioning (DP) in offshore operations. Willis (2007, p. 1) define dynamic positioning as “a system which automatically controls a vessel to maintain her position and heading exclusively by means of active thrust.” dynamic positioning plays a significant role in the maritime industry with respect to offshore operations (Liu, 2007). Dynamic positioning main advantage is its ability to correct for external forces namely wind, current and waves working on a ship (Kristiansen, 2005). Therefore, dynamic positioning enable a vessel operator to be in control of an offshore vessel, which is not only important for oil and gas exploitation but is also critical for ensuring maritime safety (Nguyen and Sørensen, 2009). Losing control of an offshore vessel can be quite disastrous since losing control of a vessel’s position can derail offshore operations and endanger human life, environment and assets. The key forces that an offshore vessel is subject to include currents, waves and wind. Willis (2007) also noted that a vessel also generates forces through propulsion system. Position reference system measures forces affecting position of a vessel. Computer system using such inputs is therefore able to calculate the difference between vessel’s actual position and required position during a negligible time interval. Shi, Phillips and Martinez (2005) noted that what follows is calculation of the thrust force needed to make the resulting change in position as small as possible. The main components of dynamic positioning system include references, control and power. Sensors according to IMCA (2007) include sensors that give environmental, vessel attitude and position information. Whereas control, is position control system and power management system (Willis, 2007). Power entails consumption, distribution and generation. Understanding components of dynamic positioning is crucial to comprehending the role and attribute of the system. Dynamic positioning is a technology that has a growing demand for the purpose of gas and oil exploitation (Fossen, 2011).

1.2         JUSTIFICATION

Dealing with the impact of natural forces on offshore vessels such as wind, current and strong waves has been a big problem a long time. However, the emergence of dynamic positioning has led to great solution for such a problem. Dynamic positioning as indicated by several authors enables an operator to be in control of an offshore vessel (Shi, Phillips and Martinez, 2005; Willis, 2007). However, effectiveness of dynamic positioning in offshore operations from the perspective of dynamic positioning operators is unknown, which forms the basis of this research. This research therefore aims to investigate effectiveness of dynamic positioning in offshore operations from perspective dynamic positioning operators.

1.3         AIM

The aim of the current study is to evaluate the development and effectiveness of dynamic positioning in offshore operations.

1.4         OBJECTIVES

Specific objectives investigated in this study include the following:

  1. To evaluate the need for dynamic positioning in offshore operations
  2. To review the existing publications on dynamic positioning classes, techniques and systems
  3. To assess the benefits of dynamic positioning of the vessel in offshore operations
  4. To examine the limitations of dynamic positioning systems

1.5         LIMITATIONS

The limitation of this study includes time, financial resource and geographical location (McBurney and White, 2009). The research was expected to be completed within a specified time, which limited the research considerably with respect to the scope of the research. In addition, the limited financial resources could not enable data collection from very many respondents. Respondents were derived from 15 marine companies thereby limiting the data collected to only 90 respondents from 15 located as specific locations.

1.6         RESEARCH OUTLINE

This research is divided into seven chapters. Chapter 1 highlights the introduction of the research topic and provide an in-depth background for the study apart from highlighting research objectives, aim, justification of the research and research outline as well as limitations. Chapter 2 provides the literature review of the studies on dynamic positioning in offshore operations apart from highlighting detailed discussion of methods and techniques as well as strategies used in the proposed research to collect and analyze data. Chapter 3 highlights dynamic positioning analysis, which includes analysis of various variables on dynamic position. Chapter 4 highlight statistical analysis of different variables about benefits of dynamic positioning. Chapter 5 also included statistical analysis on effectiveness and limitations of dynamic positioning. Chapter 6 highlights the discussion and analysis of findings while chapter 7 highlights conclusion and reflection on the study.

 

1.7         SUMMARY

Dynamic position is very important in maritime industry as well as in the energy sector since the technology allows operators to be in control of offshore vessel against strong forces of nature like wind, current and waves while undertaking offshore operations. The objectives of this research include evaluating the need for dynamic positioning in offshore operations, to review the existing publications on dynamic positioning classes, techniques and systems, to assess the benefits of dynamic positioning of the vessel in offshore operations and to examine the limitations of dynamic positioning systems. The research was divided into seven chapters: introduction, literature review and methodology, dynamic positioning analysis, benefits of dynamic positioning analysis, effectiveness and limitation of dynamic positioning analysis, discussion and analysis and conclusion and reflection.

CHAPTER 2    –     LITERATURE REVIEW AND METHODOLOGY

2.1         INTRODUCTION

Chapter 2 highlights past studies on the needs for dynamic positioning of vessel in offshore operations. The measures the international maritime organization (IMO) set in place for the safe operations of such vessel (DP) have also been discussed. Also highlighted in the current chapter include class, techniques and system design of dynamic position and what are their benefits of such system to the maritime industry.

2.2         THE NEED FOR DYNAMIC POSITION SYSTEM

Due to the depletion of our land resources, exploitation and exploration of ocean resources have increased in recent times. Dynamic positioning (DP) system has played an important role in offshore operations due to the increasing demand for oil and gas exploitation in deep sea (Fang, Leira and Blanke, 2013). This is not limited to the oil and gas industry but the system is also applied in ships, semi-submersible Mobile Offshore Drilling Unit (MODU), underwater pipe laying, offloading, diving support and Oceanographic Research vessel’s. The main purpose of which as explained in the previous chapter is to maintain a certain position and heading of a defined location or navigating along a predetermined track against the ocean disturbances due to wind, waves and current using thrusters and propellers (Sorenson, 2011; Tannuri and Morishita, 2006).

Since the introduction of dynamic positioning system, there has been a great increase in the global economic, the economic growth was estimated or expected to reach 1.48 billion US dollars by 2020, growing at the rate of 4.36 percent per year, according to the time of this report published by a research company market (Mpropulsion.com, 2015). As a result, demand and the use of Dynamic positioned vessel for offshore drilling and other operations has increased considerably (Murphy, 2004). At the time of this report, the Asia pacific region was expected to account for a major share in the market in 2015 other countries such as China, Japan and South Korea are estimated to make a fast increase within the year 2015 to 2020. Even countries such as Saudi Arabia and UAE in the Middle East identified as developing are expected to experience the upturn in the demand for dynamic positioning system. This report was concluded based on the fact that, the fluctuation on the price of oil, investing in dynamic positioning system still remain strong and self-assuring for further expansion of the technology in future. (Mpropulsion.com, 2015)

According to the research done by a research firm called Douglas-Westwood, predicted that the world subsea vessel operations market between the years 2011-2015 is expected to expand by 52% to 72billion US dollars over that period and the  demand for dynamic positioned (DP) vessel will increase by 28% from the previous five years. (Garcia, 2012)

2.3         EXISTING PUBLICATIONS

As mentioned in the introduction about the classes of dynamic positioned vessels that existed in 1994, however the international maritime organization (IMO) has finally come to an agreement of accepting to use the proposed guidelines done by the international marine contractors association (IMCA) for dynamic positioning system on the MSC Circular 645. (IMCA, 2016)

The international maritime organization (IMO) circular 645 successfully established an acceptable international standard for DP systems, that provides a framework on the regulations and classification society rules, which supplement the growth of the industry (IMCA, 2016). Since the publication of the MSC/circular 645 in 1994, there has been an evolution on the technology used for mobile offshore drilling units (MODU) maintaining the positions of offshore wells, vessels like tankers and passenger vessel. The publications has been long overdue for an amendment in other for vessels to reflect on the changes in both the technology and the industry, including performing a Failure Modes and Effect Analysis (FMEA) on the system DP and also analyzing and identifying the consequences of any single point failure such as in design or significant loss of position by drift off or drive off. A consideration by IMO to include DP equipment class 0 is to be recognized and flag state provision of certification. The IMCA is also working on achieving a good database system for DP vessels and their operating companies to use as a medium of reporting incidents for mutual benefits, the report of each year will be collected and analysed, and publish in other to create safety awareness in the industry (IMCA, 2015).

2.4          DYNAMIC DESIGN AND CONTROL SYSTEM

The early DP system was made based on conventional Proportional-Integral-Derivative (PID) controller that was available in the 1960s (Fossen, 2002). The technology was based on a multi-variable optimal control and Kalman’s filter theory was applied on the design of DP control system (Salid, Jenssen, and Balchen, 1983). Kalman’s filter theory works with the principle of motion of high frequency and low amplitude. The motion high frequency is a resultant of the first order of wave load, which affect the position, heading measurement, and the estimate of velocity, their signal are filtered and then passed to the controller and DP system compensate for such wave frequency (User, 2016).

Linearization was used to determine the vessel design, which also required on kinematic equation (Salid, Jenssen, and Balchen, 1983). In recent years, nonlinear characterization of Dynamic positioned vessels has developed rapidly since its introduction in its design, Fossen and Grovlen also derived a globally exponentially stable output feedback controller on DP system; this made use of the vectorial back stepping method (Fossen and Grovlen, 1998). The Wang et al design was also based on the nonlinear model predictive control algorithm (Wang et al, 2012). The environmental disturbance also acting on the vessel were neglected, but was restrictive in practice (Fossen and Grovlen, 1998; Wang et al, 2012).

Du et al also proposed a globally asymptotically stable output feedback by considering the unknown time- varying environmental disturbance, he also proposed a nonlinear output feedback controller through integrating a high observer into dynamic surface control techniques (Du et al, 2013). Chen and Tan also put forward nonlinear output feedback controller for DP system by combining the type-2 Mamdani Fuzzy system with a model-based passive observer provided an estimations for slowly varying environmental disturbance with waves filtering (Chen and Tan, 2010).

The aforementioned Dynamic Position was designed based on the exact vessel dynamic motion models. In reality, dynamic model parameters are difficult to be determined accurately (Hancock, Carpendale, Cockburn, 2007). Wang et al developed a fuzzy predictive controller by combining the T-S fuzzy system and the general predictive control method with environmental disturbance ignored (Wang, Xiao and Wang, 2013). Most recent Dynamic Position system has been designed to operate within a certain limit of weather conditions thereby limiting the power capacity of their thrusters. Lindeguard (2005) put forward an Acceleration Feedback (AFB); it increases the performance of the Dynamic Position system in severe weather conditions. Sorenen, Strand and Nyberg (2002) and Sorensen (2005) proposed a passive nonlinear observer without wave frequency (WF) filtering the output of the PID-controller in extreme sea especially in places where the swell are dominant.

Hespanha, (2001)  and Hespanha and Morse (2002) , Hespanha, Liberon and Morse (2003) all  proposed a fault tolerant control system which was also supported by Blanke, Kinnaert, Lunze and Staroswiecki (2003)who also added a proper control design system that incorporate architecture and formalism in the integration of multi-functional controllers combining discrete events and continuous control.

A supervisory switched controller for the Dynamic position system is used to calm the sea in extreme sea condition, from transit to station keeping operations (Berntsen, Aamo and Leira, 2006; (IMCA, 2007)). The main aim of the supervisory-switched is to integrate and appropriate bank of controller and model plants into a level of hybrid Dynamic positioning system operating at fluctuating environmental and operational conditions, Sorensen, Quek and Nguyen (2005), Nguyen (2006), Nguyen et al (2007),  Nguyen et al (2008), and Nguyen and Sorensen (2009b) did this preposition. The concept of Hybrid Dynamic positions control  was to increase the efficiency of operation at any weather working conditions in all marine operations such as subsea installations and intervention, drilling, and pipe laying in harsh environment (Norman, 2002; Mills, 2000).

2.5           CAPABILTY OF DP SYSTEM ANALYSIS

The analysis of DPCap accuracy is determined by how effective the thrust allocation logic is, as well as a precise estimation of the environmental forces and that of thrust. Estimating the environmental forces can be based on a model test, which make use of a hydrodynamic computation or an empirical formulas proposed by Sorensen and Ronass, (2001). The allocation logic of thrust can be expressed as an optimization problem, where there is a minimum use of control effort or power subject to the rate of thrusters, position constraints, power constraint and other operational constraints (Johansen et, al., 2004; Fossen and Johansen, 2006). Other optimization methods are found in Bodson, (2002) literature.

The exploration of DPCap helps to determine the maximum environmental forces that the DP system can counteract for a given heading. The investigation makes use of the vessels positions heading ranging from 0 to 360, the moment and environmental forces are statically and dynamically balanced by the thrust force, several kind of thrusters in the vessels thrust system are provided by the moment. The fundamental importance of capacity thrust is the ability of their combining capability to position a vessel, the concept of this is reported in a literature that considers the influence of individual thrusters on DPCap with an example on ABS notation station-keeping performance (SKP) and Det Norske Veritas (DNV).

The sensitivity of thrust evaluation can be used to understand the relationship between each individual thrusters and position capability as observed Baird (1989) established. It also examines the effect of the model since the design of thrust system can be changeable

2.6         FAULTS AND SAFETY OF DYNAMIC POSITIONING SYSTEM

As all other technological system suffers from one failure or another, the DP system also suffers from the same failures. Failures such as loss of positions, electrical, hydraulic or thrusters failure and some failures can be caused by the computer used in the position. The International Marine Contractors Association (IMCA) defines the guidelines for fault-tolerant system design (MSC/IMCA, 1994): as part of the requirement for a class 2 DP vessels, that a loss is positions will not occur in an event when there is a failure in any active component systems such as generators, switchboards, remote controlled valves, thrusters etc.

According to the IMCA report in 1994, it was discovered that 21% of incidents that occur on a DP are caused by thrusters and also Phillips (1996) as addressed the issues of reliability of thruster. In case of thrusters failure, it is important to recover control of system as stated in the MSC/IMCA 1994 requires a redundancy of all component to meet with a single failure criteria.

In offshore operations, the increase in safety and the efficiency of the work operations on floating platforms is attracting more attention. The dynamic positioning of surface vessels moored to the seabed, the issues of safety in an event of faults or fault-tolerant control of marine vessel presented are very challenging (Reikimoto, 2002). Normal regulations have defined the safety, fault differently by levels of hardware redundancies, and prevent failure by replacing faulty hardware (DNV, 2008). Analyzing the risk and evaluating the fault, which is based on reliability characteristic of mechanical component as such as fatigue damage or line breakage under extreme conditions (Fang et al, 2013, Gao and Moan, 2007 and Wang et al 2014). Human interaction also plays a significant role in safety and faults handling because a review of the accident database shows that human error plays a dominant factor in marine accident (Baker and McCafferly, 2005). In order to present such a risk and a reduction in cost, isolation of faults should be handled automatically by fault-tolerant control capable of positioning the vessel and system control (ABS, 2013; Sørfonn, 2007).

One of the methods of detecting faults is the structural analysis techniques (Blanke, Kinnaert and Staroswiecki 2006). Once a fault is successfully detected in the component of the system, the controller is to be re-designed in a way that fault effect can be narrow. This whole process is achievable by control re-configuration strategy, which is designed base on the type of fault and thus implemented as needed (Nguyen and Sørensen, 2009).

2.7         METHODOLOGY

2.7.1       Research design

Assessing effectiveness of dynamic positioning in offshore operations required views and opinions of dynamic positioning operator to bridge gaps left by past studies; hence, a primary research was necessary. Descriptive survey was the most appropriate in this research (Creswell and Plano Clark, 2010; Creswell, 2009). Descriptive survey using quantitative approach was the most suitable design in this research because the approach used statistical tools for inference analysis, which could not be undertaken in a qualitative research (Denzin and Lincoln, 2006). Moreover, the approached used enabled the collection of views of many respondents within a relatively shorter time compared to other methods like qualitative research (Cooper and Schindler, 2006).

2.7.2       Types and Sources of Data

Both secondary and primary data were crucial in the study of effectiveness of dynamic positioning in offshore operations. Secondary data were gathered by reviewing relevant past studies. Sources of secondary data used in this research include books, journals, periodicals, magazines and internet. On the other hand, primary data was collected directly from respondents (Cohen, Manion and Morrison, 2007). Closed ended questionnaires were used to collect the views and of the dynamic positioning system operators. Primary data played a significant role of bridging existing gaps left by past studies.

2.7.3       Participants and Sampling

Sample population in this study include dynamic positioning system operators. The designation of respondents that participated in the study includes senior dynamic positioning operator, dynamic positioning operator, dynamic positioning engineers, dynamic positioning technical officer and vessel operator. Experts in dynamic positioning were best placed to provide accurate and informed opinions and views on the subject of the study (Cozby, 2009). The sample size was 90. The researcher derived 90 respondents from 15 marine companies: six respondents from each of the 15 companies. Simple random sampling technique was used in selecting companies and respondents that participated in the study (McNeill and Chapman, 2005). The reason for the choice of the sampling technique was to ensure that the data gathered was representative of the opinions and views of the sample population as much as possible since in simple random sampling every element has equal probability (Kothari, 2008).

A list of 79 top major shipping companies was obtained from the internet using Google engine search (How to export import.com, 2016). The companies were listed alphabetical and assigned numbers from 1 to 79. Stat Trek random number generator was the used to generate 15 random numbers (Stat Trek, 2016). Companies whose assigned numbers were the same as the 15 random numbers generated were selected and the managers of the companies were contacted to give their consent. The process was repeated until 15 willing companies were identified. The managers of the companies were then asked to provide a list of 30 dynamic position operators from which six respondents were identified using the same procedure. The researcher sought the consent of the respondents before emailing to them the closed ended questionnaire for them to fill.

2.7.4       Data Collection

Closed ended questionnaire was used for data collection.

2.7.5       Questionnaire

Closed ended questionnaire was quite convenient as an instrument to use in the data collection in this study since respondents could fill the questionnaires in the absence of the researcher. Hence, the most suitable data collection method/instrument used in collecting primary data in this study was closed-ended questionnaires (McBurney and White, 2009). The researcher designed the questionnaires in accordance with the research question and objectives following the 5-likert scale.

2.7.6       Data Analysis

The researcher gathered quantitative data, which were quite difficult to understand in raw form. Hence, the data was extracted from the questionnaire for further analysis. Chi-square test and descriptive statistical analysis was used for data analysis, results presented in form of tables, and graphs.

2.7.7       Ethical Consideration

Research ethics was an important consideration throughout the research process (Denzin and Lincoln, 2006). It was important to ensure that research was not harmful in any way. In addition, the researcher explained to the institutions and respondents that participated in this research the purpose of the research before requesting their consent. Anonymity was critical and respondents were assured of their anonymity. No personal information that could lead to the identification of the respondents was allowed in the questionnaire (Fowler, 2001). The respondents were also informed of their right to withdraw from the study at any stage of without reprisal whatsoever.

2.8         SUMMARY

Chapter 2 highlights a review of past study and methods used in the currents study on the effectiveness of dynamic positioning in offshore operations. Dynamic positioning (DP) system is a very important technology. DP has played an important role in offshore operations due to the increasing demand for oil and gas exploitation in deep sea. DP has not only been used in oil and gas industry but it has also been used in ships, semi-submersible Mobile Offshore Drilling Unit, underwater pipe laying, offloading, diving support and Oceanographic Research vessel’s. Descriptive survey design was used in this research where closed ended questionnaire was used. Dynamic positioning operators formed the sample population. Sample size was 90. The researcher used chi-square test and descriptive statistical analysis to analyze quantitative data gathered in the research.

 

CHAPTER 3    –     DYNAMIC POSITIONING ANALYSIS

3.1         INTRODUCTION

Chapter three on dynamic position analysis presents demographic information analysis and analysis of various variables of dynamic position. The characteristics of the sample population investigated in this study include age, gender, work designation, level of education and conversance with subject of the study. Dynamic variables on the other hand include vessel position, changes in the location of offshore vessels, impact of current, wind, wave acting on the ship, manoeuvring flexibility and adaptation to operation requirements among others.

3.2         DEMOGRAPHIC INFORMATION

Table 3.1 (Age) indicate that 2.2% of the respondents were aged less than 18 years, 21.1% were aged 18-24 years, 56.7% were aged 25-34 years, 11.1% were aged 35-40 years and 8.9% were aged 40-60 years.

Table 3.1: Age

Age
Frequency Percent Valid Percent Cumulative Percent
Valid <18 years 2 2.2 2.2 2.2
18 – 24 years 19 21.1 21.1 23.3
25 – 34 years 51 56.7 56.7 80.0
35 – 40 years 10 11.1 11.1 91.1
40 – 60 years 8 8.9 8.9 100.0
Total 90 100.0 100.0

 

Figure 3.1: Age

 

 

 

 

 

 

 

 

Table 3.2 on education level shows that 1.1% of the respondents had O/A level of education, 6.7% had diploma, 46.7% had Bachelor’s degree, 30% had Master’s degree and 15.6% had doctorate degree.

Table 3.2: Education Level

Education Level
Frequency Percent Valid Percent Cumulative Percent
Valid O/A – Level 1 1.1 1.1 1.1
Diploma 6 6.7 6.7 7.8
Bachelor’s degree 42 46.7 46.7 54.4
Master’s degree 27 30.0 30.0 84.4
Doctorate degree 14 15.6 15.6 100.0
Total 90 100.0 100.0

Figure 3.2: Education Level

 

 

Table 3.3 on Gender shows that 68.9% of the respondents were male while female comprised 31.1%.

Table 3.3: Gender

Gender
Frequency Percent Valid Percent Cumulative Percent
Valid Male 62 68.9 68.9 68.9
Female 28 31.1 31.1 100.0
Total 90 100.0 100.0

 

Figure 3.3: Gender

 

 

 

 

 

 

 

 

 

Table 3.4 on work designation indicates that 16.7% of the respondents were Senior Dynamic Positioning Operator, 22.2% were Dynamic Positioning Operator, 25.6% were Dynamic Positioning Engineer, 28.9% were Dynamic Positioning Technical officer and 6.7% were vessel operator.

Table 3.4: Work Designation

Work Designation
Frequency Percent Valid Percent Cumulative Percent
Valid Senior Dynamic Positioning Operator 15 16.7 16.7 16.7
Dynamic Positioning Operator 20 22.2 22.2 38.9
Dynamic Positioning Engineer 23 25.6 25.6 64.4
Dynamic Positioning Technical officer 26 28.9 28.9 93.3
Vessel Operator 6 6.7 6.7 100.0
Total 90 100.0 100.0

Figure 3.4: Work Designation

 

 

Table 3.5 on conversance shows that 1.1% of the respondents strongly disagreed they were familiar with the subject of the effectiveness of dynamic positioning in offshore operations. Moreover, 2.2% disagrees, 2.2% neither agreed nor disagreed, 16.7% agreed and 77.8% strongly agreed.

Table 3.5: Conversance with the subject of the effectiveness of dynamic positioning in offshore operations

Do you regard yourself as being familiar with the subject of the effectiveness of dynamic positioning in offshore operations?
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 1 1.1 1.1 1.1
Disagree 2 2.2 2.2 3.3
Neither agree nor disagree 2 2.2 2.2 5.6
Agree 15 16.7 16.7 22.2
Strongly Agree 70 77.8 77.8 100.0
Total 90 100.0 100.0

Figure 3.5: Conversance with the subject of the effectiveness of dynamic positioning in offshore operations

 

3.3         DESCRIPTIVE STATISTICAL ANALYSIS

Table 3.6 shows the level of agreement of respondent regarding the statement “Dynamic positioning system plays an important role in offshore operations.” From the table 2.2% of the respondents strongly disagreed with the statement, 2.2% disagreed, 8.9% neither agreed nor disagreed and 22.2% agreed while 64.4% strongly agreed.

Table 3.6: Dynamic positioning system plays an important role in offshore operations

Dynamic positioning system plays an important role in offshore operations
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 2 2.2 2.2 2.2
Disagree 2 2.2 2.2 4.4
Neither agree nor disagree 8 8.9 8.9 13.3
Agree 20 22.2 22.2 35.6
Strongly Agree 58 64.4 64.4 100.0
Total 90 100.0 100.0

Figure 3.6: Dynamic positioning system plays an important role in offshore operations

 

Table 3.7 shows the level of agreement of respondent regarding the statement “Dynamic positioning enables offshore vessels to stay in position.” From the table 2.2% of the respondents strongly disagreed with the statement,4.4 % disagreed, 4.4% neither agreed nor disagreed and 26.7% agreed while 62.2% strongly agreed.

Table 3.7: Dynamic positioning enables offshore vessels to stay in position

Dynamic positioning enables offshore vessels to stay in position
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 2 2.2 2.2 2.2
Disagree 4 4.4 4.4 6.7
Neither agree nor disagree 4 4.4 4.4 11.1
Agree 24 26.7 26.7 37.8
Strongly Agree 56 62.2 62.2 100.0
Total 90 100.0 100.0

 

Figure 3.7: Dynamic positioning enables offshore vessels to stay in position

 

Table 3.8 shows the level of agreement of respondent regarding the statement “Dynamic positioning overcome changes in the location of offshore vessels.” From the table 2.2% of the respondents strongly disagreed with the statement, 4.4% disagreed, 8.9% neither agreed nor disagreed and 22.2% agreed while 62.2% strongly agreed.

Table 3.8: Dynamic positioning overcome changes in the location of offshore vessels

Dynamic positioning uses computer technologies to overcome changes in the location of offshore vessels
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 2 2.2 2.2 2.2
Disagree 4 4.4 4.4 6.7
Neither agree nor disagree 8 8.9 8.9 15.6
Agree 20 22.2 22.2 37.8
Strongly Agree 56 62.2 62.2 100.0
Total 90 100.0 100.0

Figure 3.8: Dynamic positioning overcome changes in the location of offshore vessels

 

Table 3.9 shows the level of agreement of respondent regarding the statement “Dynamic positioning system prevent the impact of current, wind, wave acting on the ship.” From the table 3.3% of the respondents strongly disagreed with the statement, 6.7% disagreed, 6.7% neither agreed nor disagreed and 35.6% agreed while 46.8% strongly agreed.

Table 3.9: Dynamic positioning system prevent the impact of current, wind, wave acting on the ship

Dynamic positioning system prevent the impact of current, wind, wave acting on the ship
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 6 6.7 6.7 10.0
Neither agree nor disagree 6 6.7 6.7 16.7
Agree 32 35.6 35.6 52.2
Strongly Agree 43 47.8 47.8 100.0
Total 90 100.0 100.0

Figure 3.9: Dynamic positioning system prevent the impact of current, wind, wave acting on the ship

Table 3.10 shows the level of agreement of respondent regarding the statement “Dynamic positioning allows greater manoeuvring flexibility.” From the table 4.4% of the respondents strongly disagreed with the statement, 6.7% disagreed, 7.8% neither agreed nor disagreed and 26.7% agreed while 54.4% strongly agreed.

Table 3.10: Dynamic positioning allows greater manoeuvring flexibility

Dynamic positioning allows greater manoeuvring flexibility
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 6 6.7 6.7 11.1
Neither agree nor disagree 7 7.8 7.8 18.9
Agree 24 26.7 26.7 45.6
Strongly Agree 49 54.4 54.4 100.0
Total 90 100.0 100.0

Figure 3.10: Dynamic positioning allow greater manoeuvring flexibility

 

 

Table 3.11 shows the level of agreement of respondent regarding the statement “Dynamic positioning is advantageous compared to Jack-up barge and spread mooring to anchor pattern.” From the table 4.4% of the respondents strongly disagreed with the statement, 5.6% disagreed, 6.7% neither agreed nor disagreed and 14.4% agreed while 68.9% strongly agreed.

Table 3.11: Dynamic positioning is advantageous compared to Jack-up barge and spread mooring to anchor pattern

Dynamic positioning is advantageous compared to other systems like Jack-up barge and spread mooring to anchor pattern
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 5 5.6 5.6 10.0
Neither agree nor disagree 6 6.7 6.7 16.7
Agree 13 14.4 14.4 31.1
Strongly Agree 62 68.9 68.9 100.0
Total 90 100.0 100.0

Figure 3.11: Dynamic positioning is advantageous compared Jack-up barge and spread mooring to anchor pattern

Table 3.12 shows the level of agreement of respondent regarding the statement “Dynamic positioning system is capable of reacting to weather changes.” From the table 5.6% of the respondents strongly disagreed with the statement, 10% disagreed, 11.1% neither agreed nor disagreed and 35.6% agreed while 37.8% strongly agreed.

Table 3.12: Dynamic positioning system is capable of reacting to weather changes

Dynamic positioning system is capable of reacting to weather changes
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 9 10.0 10.0 15.6
Neither agree nor disagree 10 11.1 11.1 26.7
Agree 32 35.6 35.6 62.2
Strongly Agree 34 37.8 37.8 100.0
Total 90 100.0 100.0

Figure 3.12: Dynamic positioning system is capable of reacting to weather changes

 

 

 

Table 3.13 shows the level of agreement of respondent regarding the statement “Dynamic positioning is able to adapt to operation requirements.” From the table 4.4% of the respondents strongly disagreed with the statement, 4.4% disagreed, 3.3% neither agreed nor disagreed and 35.6% agreed while 52.2% strongly agreed.

Table 3.13: Dynamic positioning is able to adapt to operation requirements

Dynamic positioning is able to adapt to operation requirements
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 4 4.4 4.4 8.9
Neither agree nor disagree 3 3.3 3.3 12.2
Agree 32 35.6 35.6 47.8
Strongly Agree 47 52.2 52.2 100.0
Total 90 100.0 100.0

Figure 3.13: Dynamic positioning is able to adapt to operation requirements

 

 

Table 3.14 shows the level of agreement of respondent regarding the statement “The use of dynamic positioning system comes with less risk for environment.” From the table 2.2% of the respondents strongly disagreed with the statement, 4.4% disagreed, 7.8% neither agreed nor disagreed and 41.1% agreed while 44.4% strongly agreed.

Table 3.14: The use of dynamic positioning system comes with less risk for environment

The use of dynamic positioning system comes with less risk for environment since it does not cause mooring line on the seabed
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 2 2.2 2.2 2.2
Disagree 4 4.4 4.4 6.7
Neither agree nor disagree 7 7.8 7.8 14.4
Agree 37 41.1 41.1 55.6
Strongly Agree 40 44.4 44.4 100.0
Total 90 100.0 100.0

Figure 3.14: The use of dynamic positioning system comes with less risk for environment

 

3.4         CHI-SQUARE TESTS

3.4.1.1                Test 1

The investigator used chi-square tests to investigate the relationship between different variable. To establish the association between “Dynamic positioning system plays an important role in offshore operations” and “Dynamic positioning enable offshore vessels to stay in position,” the researcher conducted a chi-square test for equal proportion and Table 3.15 (Dynamic positioning system and ability of offshore vessels to stay in position) and Table 3.16 (Chi-Square Tests) show the findings.

Table 3.15: Dynamic positioning system and ability of offshore vessels to stay in position

Dynamic positioning system plays an important role in offshore operations * Dynamic positioning enable offshore vessels to stay in position Crosstabulation
Dynamic positioning enable offshore vessels to stay in position Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning system plays an important role in offshore operations Strongly disagree Count 0 0 1 0 1 2
% of Total 0.0% 0.0% 1.1% 0.0% 1.1% 2.2%
Disagree Count 0 0 0 0 2 2
% of Total 0.0% 0.0% 0.0% 0.0% 2.2% 2.2%
Neither agree nor disagree Count 0 1 1 6 0 8
% of Total 0.0% 1.1% 1.1% 6.7% 0.0% 8.9%
Agree Count 0 2 0 8 10 20
% of Total 0.0% 2.2% 0.0% 8.9% 11.1% 22.2%
Strongly Agree Count 2 1 2 10 43 58
% of Total 2.2% 1.1% 2.2% 11.1% 47.8% 64.4%
Total Count 2 4 4 24 56 90
% of Total 2.2% 4.4% 4.4% 26.7% 62.2% 100.0%

Table 3.16 indicates a p value of 0.004, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning system and ability of offshore vessels to stay in position. Table 3.15 shows that more than 86% of the respondents who agreed with the statement “Dynamic positioning system plays an important role in offshore operations” also agreed, “Dynamic positioning enable offshore vessels to stay in position.”

Table 3.16: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 35.047a 16 .004
Likelihood Ratio 33.399 16 .007
Linear-by-Linear Association 3.512 1 .061
N of Valid Cases 90
a. 21 cells (84.0%) have expected count less than 5. The minimum expected count is .04.

 

3.4.1.2                Test 2

To establish the association between “Dynamic positioning system plays an important role in offshore operations” and “Dynamic positioning allow greater manoeuvring flexibility,” the researcher conducted a chi-square test for equal proportion and Table 3.17 (Chi-Square Tests) and Table 3.18 (Dynamic positioning system and manoeuvring flexibility) show the findings.

Table 3.17: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 31.143a 16 .013
Likelihood Ratio 28.419 16 .028
Linear-by-Linear Association 2.731 1 .098
N of Valid Cases 90
a. 21 cells (84.0%) have expected count less than 5. The minimum expected count is .09.

Table 3.18: Dynamic positioning system and manoeuvring flexibility

Dynamic positioning system plays an important role in offshore operations * Dynamic positioning allow greater manoeuvring flexibility  Crosstabulation
Dynamic positioning allow greater manoeuvring flexibility Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning system plays an important role in offshore operations Strongly disagree Count 0 0 1 0 1 2
% of Total 0.0% 0.0% 1.1% 0.0% 1.1% 2.2%
Disagree Count 0 1 0 0 1 2
% of Total 0.0% 1.1% 0.0% 0.0% 1.1% 2.2%
Neither agree nor disagree Count 0 1 2 0 5 8
% of Total 0.0% 1.1% 2.2% 0.0% 5.6% 8.9%
Agree Count 1 3 1 10 5 20
% of Total 1.1% 3.3% 1.1% 11.1% 5.6% 22.2%
Strongly Agree Count 3 1 3 14 37 58
% of Total 3.3% 1.1% 3.3% 15.6% 41.1% 64.4%
Total Count 4 6 7 24 49 90
% of Total 4.4% 6.7% 7.8% 26.7% 54.4% 100.0%

 

Table 3.17 indicates a p value of 0.013, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning system and manoeuvring flexibility. Table 3.18 shows that more than 81% of the respondents who agreed with the statement “Dynamic positioning system plays an important role in offshore operations” also agreed, “Dynamic positioning allow greater manoeuvring flexibility.”

3.4.1.3                Test 3

To establish the association between “Dynamic positioning system plays an important role in offshore operations” and “Dynamic positioning system is capable of reacting to weather changes,” the researcher conducted a chi-square test for equal proportion and Table 3.19 (Dynamic positioning system and its capability to react to weather changes) and Table 3.20 (Chi-Square Tests) show the findings.

Table 3.19: Dynamic positioning system and its capability to react to weather changes

Dynamic positioning system plays an important role in offshore operations * Dynamic positioning system is capable of reacting to weather changes Crosstabulation
Dynamic positioning system is capable of reacting to weather changes Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning system plays an important role in offshore operations Strongly disagree Count 1 0 0 0 1 2
% of Total 1.1% 0.0% 0.0% 0.0% 1.1% 2.2%
Disagree Count 0 0 1 0 1 2
% of Total 0.0% 0.0% 1.1% 0.0% 1.1% 2.2%
Neither agree nor disagree Count 0 1 1 2 4 8
% of Total 0.0% 1.1% 1.1% 2.2% 4.4% 8.9%
Agree Count 3 4 0 12 1 20
% of Total 3.3% 4.4% 0.0% 13.3% 1.1% 22.2%
Strongly Agree Count 1 4 8 18 27 58
% of Total 1.1% 4.4% 8.9% 20.0% 30.0% 64.4%
Total Count 5 9 10 32 34 90
% of Total 5.6% 10.0% 11.1% 35.6% 37.8% 100.0%

 

Table 3.20 indicates a p value of 0.006, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning system and its capability to react to weather changes. Table 3.19 shows that more than 73% of the respondents who agreed with the statement “Dynamic positioning system plays an important role in offshore operations” also agreed, “Dynamic positioning system is capable of reacting to weather changes.”

Table 3.20: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 33.687a 16 .006
Likelihood Ratio 34.586 16 .005
Linear-by-Linear Association 2.792 1 .095
N of Valid Cases 90
a. 19 cells (76.0%) have expected count less than 5. The minimum expected count is .11.

 

3.5         SUMMARY

The findings on analysis of characteristics of sample population show that that majority of the respondents were aged over 25 years. Besides, majority were male with at least bachelor’s degree. Respondents were employees working on dynamic position system. Moreover, majority of the respondents agreed with statements of all variable. Inferential analysis showed that there was significant relationship between various variable.

CHAPTER 4    –     BENEFITS OF DYNAMIC POSITIONING ANALYSIS

4.1         INTRODUCTION

Analysis of benefits of dynamic position chapter highlights descriptive statistical analysis and chi-square test of different variables. The inferential analysis aimed to investigate relationship of various variables in the study.

4.2         DESCRIPTIVE STATISTICAL ANALYSIS

Table 4.1 shows the level of agreement of respondent regarding the statement “Dynamic positioning help in increasing demand for oil and gas exploitation in deep sea.” From the table 5.6% of the respondents strongly disagreed with the statement, 7.8% disagreed, 6.7% neither agreed nor disagreed and 35.6% agreed while 44.4% strongly agreed.

Table 4.1: Dynamic positioning help in increasing demand for oil and gas exploitation in deep sea

Dynamic positioning help in increasing demand for oil and gas exploitation in deep sea
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 7 7.8 7.8 13.3
Neither agree nor disagree 6 6.7 6.7 20.0
Agree 32 35.6 35.6 55.6
Strongly Agree 40 44.4 44.4 100.0
Total 90 100.0 100.0

 

Figure 4.1: Dynamic positioning help in increasing demand for oil and gas exploitation in deep sea

 

 

 

 

 

 

 

 

 

Table 4.2 shows the level of agreement of respondent regarding the statement “Dynamic positioning has many important benefits in Maritime industry.” From the table 2.2% of the respondents strongly disagreed with the statement, 3.3% disagreed, 10% neither agreed nor disagreed and 35.6% agreed while 48.9% strongly agreed.

Table 4.2: Dynamic positioning has many important benefits in Maritime industry

Dynamic positioning has many important benefits in Maritime industry
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 2 2.2 2.2 2.2
Disagree 3 3.3 3.3 5.6
Neither agree nor disagree 9 10.0 10.0 15.6
Agree 32 35.6 35.6 51.1
Strongly Agree 44 48.9 48.9 100.0
Total 90 100.0 100.0

Figure 4.2: Dynamic positioning has many important benefits in Maritime industry

 

 

Table 4.3 shows the level of agreement of respondent regarding the statement “Dynamic positioning has contributed in increasing global economic growth.” From the table 3.3% of the respondents strongly disagreed with the statement, 7.8% disagreed, 5.6% neither agreed nor disagreed and 33.3% agreed while 50% strongly agreed.

Table 4.3: Dynamic positioning has contributed in increasing global economic growth

Dynamic positioning has contributed in increasing global economic growth
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 7 7.8 7.8 11.1
Neither agree nor disagree 5 5.6 5.6 16.7
Agree 30 33.3 33.3 50.0
Strongly Agree 45 50.0 50.0 100.0
Total 90 100.0 100.0

Figure 4.3: Dynamic positioning has contributed in increasing global economic growth

 

 

Table 4.4 shows the level of agreement of respondent regarding the statement “Dynamic positioning saves time.” From the table 3.3% of the respondents strongly disagreed with the statement, 4.4% disagreed, 11.1% neither agreed nor disagreed and 34.4% agreed while 46.7% strongly agreed.

Table 4.4: Dynamic positioning saves time

Dynamic positioning saves time
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 4 4.4 4.4 7.8
Neither agree nor disagree 10 11.1 11.1 18.9
Agree 31 34.4 34.4 53.3
Strongly Agree 42 46.7 46.7 100.0
Total 90 100.0 100.0

Figure 4.4: Dynamic positioning saves time

 

 

Table 4.5 shows the level of agreement of respondent regarding the statement “Dynamic positioning system is not dependent on water depth.” From the table 4.4% of the respondents strongly disagreed with the statement, 8.9% disagreed, 6.7% neither agreed nor disagreed and 33.3% agreed while 46.7% strongly agreed.

Table 4.5: Dynamic positioning system is not dependent on water depth

Dynamic positioning system is not dependent on water depth
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 8 8.9 8.9 13.3
Neither agree nor disagree 6 6.7 6.7 20.0
Agree 30 33.3 33.3 53.3
Strongly Agree 42 46.7 46.7 100.0
Total 90 100.0 100.0

Figure 4.5: Dynamic positioning system is not dependent on water depth

 

 

Table 4.6 shows the level of agreement of respondent regarding the statement “Dynamic positioning allows quick set up.” From the table 6.7% of the respondents strongly disagreed with the statement, 4.4% disagreed, 10% neither agreed nor disagreed and 34.4% agreed while 44.4% strongly agreed.

Table 4.6: Dynamic positioning allows quick set up

Dynamic positioning allows quick set up
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 6 6.7 6.7 6.7
Disagree 4 4.4 4.4 11.1
Neither agree nor disagree 9 10.0 10.0 21.1
Agree 31 34.4 34.4 55.6
Strongly Agree 40 44.4 44.4 100.0
Total 90 100.0 100.0

Figure 4.6: Dynamic positioning allows quick set up

 

 

Table 4.7 shows the level of agreement of respondent regarding the statement “Dynamic positioning is not limited by obstructed seabed.” From the table 6.7% of the respondents strongly disagreed with the statement, 11.1% disagreed, 10% neither agreed nor disagreed and 33.3% agreed while 38.9% strongly agreed.

Table 4.7: Dynamic positioning is not limited by obstructed seabed

Dynamic positioning is not limited by obstructed seabed
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 6 6.7 6.7 6.7
Disagree 10 11.1 11.1 17.8
Neither agree nor disagree 9 10.0 10.0 27.8
Agree 30 33.3 33.3 61.1
Strongly Agree 35 38.9 38.9 100.0
Total 90 100.0 100.0

Figure 4.7: Dynamic positioning is not limited by obstructed seabed

 

 

 

Table 4.8 shows the level of agreement of respondent regarding the statement “Dynamic positioning does not need anchor handling tugs.” From the table 4.4% of the respondents strongly disagreed with the statement, 12.2% disagreed, 10% neither agreed nor disagreed and 40% agreed while 33.3% strongly agreed.

Table 4.8: Dynamic positioning does not need anchor handling tugs

Dynamic positioning does not need anchor handling tugs
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 11 12.2 12.2 16.7
Neither agree nor disagree 9 10.0 10.0 26.7
Agree 36 40.0 40.0 66.7
Strongly Agree 30 33.3 33.3 100.0
Total 90 100.0 100.0

Figure 4.8: Dynamic positioning does not need anchor handling tugs

 

 

Table 4.9 shows the level of agreement of respondent regarding the statement “Dynamic positioning saves money through low fuel cost among other factors.” From the table 5.6% of the respondents strongly disagreed with the statement, 5.6% disagreed, 8.9% neither agreed nor disagreed and 33.3% agreed while 46.7% strongly agreed.

Table 4.9: Dynamic positioning saves money through low fuel cost among other factors

Dynamic positioning saves money through low fuel cost among other factors
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 5 5.6 5.6 11.1
Neither agree nor disagree 8 8.9 8.9 20.0
Agree 30 33.3 33.3 53.3
Strongly Agree 42 46.7 46.7 100.0
Total 90 100.0 100.0

Figure 4.9: Dynamic positioning saves money through low fuel cost among other factors

 

 

 

Table 4.10 shows the level of agreement of respondent regarding the statement “Dynamic positioning saves money due to no expenditure on tugboats.” From the table 5.6% of the respondents strongly disagreed with the statement, 6.7% disagreed, 7.8% neither agreed nor disagreed and 34.4% agreed while 45.6% strongly agreed.

Table 4.10: Dynamic positioning saves money due to no expenditure on tugboats

Dynamic positioning saves money due to no expenditure on tugboats
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 6 6.7 6.7 12.2
Neither agree nor disagree 7 7.8 7.8 20.0
Agree 31 34.4 34.4 54.4
Strongly Agree 41 45.6 45.6 100.0
Total 90 100.0 100.0

Figure 4.10: Dynamic positioning saves money due to no expenditure on tugboats

 

 

Table 4.11 shows the level of agreement of respondent regarding the statement “Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces.” From the table 4.4% of the respondents strongly disagreed with the statement, 7.8% disagreed, 8.9% neither agreed nor disagreed and 35.6% agreed while 43.3% strongly agreed.

Table 4.11: Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces

Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 7 7.8 7.8 12.2
Neither agree nor disagree 8 8.9 8.9 21.1
Agree 32 35.6 35.6 56.7
Strongly Agree 39 43.3 43.3 100.0
Total 90 100.0 100.0

Figure 4.11: Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces

 

4.3         CHI-SQUARE TESTS

4.3.1.1                Test 1

To establish the association between “Dynamic positioning has many important benefits in Maritime industry” and “Dynamic positioning saves time,” the researcher conducted a chi-square test for equal proportion and Table 4.12 (Dynamic positioning and time saving) and Table 4.13 (Chi-Square Tests) show the findings.

Table 4.12: Dynamic positioning and time saving

Dynamic positioning has many important benefits in Maritime industry * Dynamic positioning saves time Crosstabulation
Dynamic positioning saves time Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning has many important benefits in Maritime industry Strongly disagree Count 0 0 0 0 2 2
% of Total 0.0% 0.0% 0.0% 0.0% 2.2% 2.2%
Disagree Count 0 0 0 1 2 3
% of Total 0.0% 0.0% 0.0% 1.1% 2.2% 3.3%
Neither agree nor disagree Count 0 0 4 4 1 9
% of Total 0.0% 0.0% 4.4% 4.4% 1.1% 10.0%
Agree Count 1 2 2 20 7 32
% of Total 1.1% 2.2% 2.2% 22.2% 7.8% 35.6%
Strongly Agree Count 2 2 4 6 30 44
% of Total 2.2% 2.2% 4.4% 6.7% 33.3% 48.9%
Total Count 3 4 10 31 42 90
% of Total 3.3% 4.4% 11.1% 34.4% 46.7% 100.0%

 

Table 4.13 indicates a p value of 0.001, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning and time saving. Table 4.12 shows that more than 81% of the respondents who agreed with the statement “Dynamic positioning has many important benefits in Maritime industry” also agreed, “Dynamic positioning saves time.”

Table 4.13: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 38.209a 16 .001
Likelihood Ratio 38.182 16 .001
Linear-by-Linear Association .333 1 .564
N of Valid Cases 90
a. 21 cells (84.0%) have expected count less than 5. The minimum expected count is .07.

 

4.3.1.2                Test 2

To establish the association between “Dynamic positioning has many important benefits in Maritime industry” and “Dynamic positioning system is not dependent on water depth,” the researcher conducted a chi-square test for equal proportion and Table 4.14 (Chi-Square Tests) and Table 4.15 (Dynamic positioning and dependence on water depth) show the findings.

 

Table 4.14: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 27.594a 16 .035
Likelihood Ratio 20.320 16 .206
Linear-by-Linear Association .992 1 .319
N of Valid Cases 90
a. 21 cells (84.0%) have expected count less than 5. The minimum expected count is .09.

 

Table 4.15: Dynamic positioning and dependence on water depth

Dynamic positioning has many important benefits in Maritime industry * Dynamic positioning system is not dependent on water depth Crosstabulation
Dynamic positioning system is not dependent on water depth Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning has many important benefits in Maritime industry Strongly disagree Count 1 0 0 0 1 2
% of Total 1.1% 0.0% 0.0% 0.0% 1.1% 2.2%
Disagree Count 0 1 0 1 1 3
% of Total 0.0% 1.1% 0.0% 1.1% 1.1% 3.3%
Neither agree nor disagree Count 0 0 3 2 4 9
% of Total 0.0% 0.0% 3.3% 2.2% 4.4% 10.0%
Agree Count 1 3 0 14 14 32
% of Total 1.1% 3.3% 0.0% 15.6% 15.6% 35.6%
Strongly Agree Count 2 4 3 13 22 44
% of Total 2.2% 4.4% 3.3% 14.4% 24.4% 48.9%
Total Count 4 8 6 30 42 90
% of Total 4.4% 8.9% 6.7% 33.3% 46.7% 100.0%

 

Table 4.14 indicates a p value of 0.035, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning and dependence on water depth. Table 4.15 shows that more than 97% of the respondents who agreed with the statement “Dynamic positioning has many important benefits in Maritime industry” also agreed, “Dynamic positioning system is not dependent on water depth.”

 

 

4.3.1.3                Test 3

To establish the association between “Dynamic positioning has many important benefits in Maritime industry” and “Dynamic positioning saves money through low fuel cost among other factors,” the researcher conducted a chi-square test for equal proportion and Table 4.16 (Dynamic positioning and saving money through low fuel cost) and Table 4.17 (Chi-Square Tests) show the findings.

Table 4.16: Dynamic positioning and saving money through low fuel cost

 

Dynamic positioning has many important benefits in Maritime industry * Dynamic positioning saves money through low fuel cost among other factors Crosstabulation
Dynamic positioning saves money through low fuel cost among other factors Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning has many important benefits in Maritime industry Strongly disagree Count 0 0 0 0 2 2
% of Total 0.0% 0.0% 0.0% 0.0% 2.2% 2.2%
Disagree Count 0 0 1 0 2 3
% of Total 0.0% 0.0% 1.1% 0.0% 2.2% 3.3%
Neither agree nor disagree Count 0 0 3 3 3 9
% of Total 0.0% 0.0% 3.3% 3.3% 3.3% 10.0%
Agree Count 2 1 3 20 6 32
% of Total 2.2% 1.1% 3.3% 22.2% 6.7% 35.6%
Strongly Agree Count 3 4 1 7 29 44
% of Total 3.3% 4.4% 1.1% 7.8% 32.2% 48.9%
Total Count 5 5 8 30 42 90
% of Total 5.6% 5.6% 8.9% 33.3% 46.7% 100.0%

 

Table 4.17 indicates a p value of 0.002, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning and saving money through low fuel cost. Table 4.16 shows that more than 80% of the respondents who agreed with the statement “Dynamic positioning has many important benefits in Maritime industry” also agreed, “Dynamic positioning saves money through low fuel cost among other factors.”

Table 4.17:Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 37.955a 16 .002
Likelihood Ratio 38.983 16 .001
Linear-by-Linear Association .005 1 .944
N of Valid Cases 90
a. 21 cells (84.0%) have expected count less than 5. The minimum expected count is .11.

 

4.4         SUMMARY

The findings on the benefits of dynamic position indicate that majority of the respondents agreed that the benefits include increasing global economic growth, the system saves time, the system is not dependent on water depth and that dynamic positioning system allows quick set up. Others include the fact that the system is not limited by obstructed seabed and it saves money through low fuel cost among other factors.

CHAPTER 5    –     EFFECTIVENESS AND LIMITATIONS OF DYNAMIC POSITIONING ANALYSIS

5.1         INTRODUCTION

Chapter 5 presents statistical analysis of variable of effectiveness and limitation of dynamic positioning. Chi-square tests and descriptive statistical analysis was used for data analysis. Relationships between different variables are also tested using chi-square test.

5.2         DESCRIPTIVE STATISTICAL ANALYSIS

Table 5.1 shows the level of agreement of respondent regarding the statement “Dynamic positioning has both effectiveness and limitations.” From the table 6.7% of the respondents strongly disagreed with the statement, 11.1% disagreed, 10% neither agreed nor disagreed and 31.1% agreed while 41.1% strongly agreed.

Table 5.1: Dynamic positioning has both effectiveness and limitations

Dynamic positioning has both effectiveness and limitations
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 6 6.7 6.7 6.7
Disagree 10 11.1 11.1 17.8
Neither agree nor disagree 9 10.0 10.0 27.8
Agree 28 31.1 31.1 58.9
Strongly Agree 37 41.1 41.1 100.0
Total 90 100.0 100.0

 

Figure 5.1: Dynamic positioning has both effectiveness and limitations

 

 

 

 

 

 

 

 

 

 

 

Table 5.2 shows the level of agreement of respondent regarding the statement “Dynamic positioning enables the operator to have full control of the vessel.” From the table 5.6% of the respondents strongly disagreed with the statement, 12.2% disagreed, 11.1% neither agreed nor disagreed and 45.6% agreed while 25.6% strongly agreed.

Table 5.2: Dynamic positioning enables the operator to have full control of the vessel

Dynamic positioning enables the operator to have full control of the vessel
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 11 12.2 12.2 17.8
Neither agree nor disagree 10 11.1 11.1 28.9
Agree 41 45.6 45.6 74.4
Strongly Agree 23 25.6 25.6 100.0
Total 90 100.0 100.0

Figure 5.2: Dynamic positioning enables the operator to have full control of the vessel

 

 

Table 5.3 shows the level of agreement of respondent regarding the statement “Dynamic positioning system is capable of maintaining required heading automatically.” From the table 7.8% of the respondents strongly disagreed with the statement, 6.7% disagreed, 13.3% neither agreed nor disagreed and 27.8% agreed while 44.4% strongly agreed.

Table 5.3: Dynamic positioning system is capable of maintaining required heading automatically

Dynamic positioning system is capable of maintaining required heading automatically
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 7 7.8 7.8 7.8
Disagree 6 6.7 6.7 14.4
Neither agree nor disagree 12 13.3 13.3 27.8
Agree 25 27.8 27.8 55.6
Strongly Agree 40 44.4 44.4 100.0
Total 90 100.0 100.0

Figure 5.3: Dynamic positioning system is capable of maintaining required heading automatically

 

 

Table 5.4 shows the level of agreement of respondent regarding the statement “Dynamic positioning system is capable of maintaining required position automatically.” From the table 1.1% of the respondents strongly disagreed with the statement, 4.4% disagreed, 5.6% neither agreed nor disagreed and 37.8% agreed while 51.1% strongly agreed.

Table 5.4: Dynamic positioning system is capable of maintaining required position automatically

Dynamic positioning system is capable of maintaining required position automatically
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 1 1.1 1.1 1.1
Disagree 4 4.4 4.4 5.6
Neither agree nor disagree 5 5.6 5.6 11.1
Agree 34 37.8 37.8 48.9
Strongly Agree 46 51.1 51.1 100.0
Total 90 100.0 100.0

Figure 5.4: Dynamic positioning system is capable of maintaining required position automatically

Table 5.5 shows the level of agreement of respondent regarding the statement “Dynamic positioning can be used in situations where a lot of precision is needed.” From the table 3.3% of the respondents strongly disagreed with the statement, 5.6% disagreed, 7.8% neither agreed nor disagreed and 35.6% agreed while 47.8% strongly agreed.

Table 5.5: Dynamic positioning can be used in situations where a lot of precision is needed

Dynamic positioning can be used in situations where a lot of precision is needed
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 5 5.6 5.6 8.9
Neither agree nor disagree 7 7.8 7.8 16.7
Agree 32 35.6 35.6 52.2
Strongly Agree 43 47.8 47.8 100.0
Total 90 100.0 100.0

Figure 5.5: Dynamic positioning can be used in situations where a lot of precision is needed

 

Table 5.6 shows the level of agreement of respondent regarding the statement “Dynamic positioning can be used on locations where other systems cannot be applied.” From the table 3.3% of the respondents strongly disagreed with the statement, 6.7% disagreed, 6.7% neither agreed nor disagreed and 42.2% agreed while 41.1% strongly agreed.

Table 5.6: Dynamic positioning can be used on locations where other systems cannot be applied

Dynamic positioning can be used on locations where other systems cannot be applied
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 6 6.7 6.7 10.0
Neither agree nor disagree 6 6.7 6.7 16.7
Agree 38 42.2 42.2 58.9
Strongly Agree 37 41.1 41.1 100.0
Total 90 100.0 100.0

Figure 5.6: Dynamic positioning can be used on locations where other systems cannot be applied

 

 

Table 5.7 shows the level of agreement of respondent regarding the statement “Operating dynamic positioning requires highly educated staff members.” From the table 3.3% of the respondents strongly disagreed with the statement, 8.9% disagreed, 8.9% neither agreed nor disagreed and 31.1% agreed while 47.8% strongly agreed.

Table 5.7: Operating dynamic positioning requires highly educated staff members

Operating dynamic positioning requires highly educated staff members
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 8 8.9 8.9 12.2
Neither agree nor disagree 8 8.9 8.9 21.1
Agree 28 31.1 31.1 52.2
Strongly Agree 43 47.8 47.8 100.0
Total 90 100.0 100.0

Figure 5.7: Operating dynamic positioning require highly educated staff members

 

 

 

 

Table 5.8 shows the level of agreement of respondent regarding the statement “Dynamic positioning require position reference continuously.” From the table 5.6% of the respondents strongly disagreed with the statement, 7.8% disagreed, 12.2% neither agreed nor disagreed and 48.9% agreed while 25.6% strongly agreed.

Table 5.8: Dynamic positioning require position reference continuously

Dynamic positioning require position reference continuously
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 7 7.8 7.8 13.3
Neither agree nor disagree 11 12.2 12.2 25.6
Agree 44 48.9 48.9 74.4
Strongly Agree 23 25.6 25.6 100.0
Total 90 100.0 100.0

Figure 5.8: Dynamic positioning require position reference continuously

 

 

Table 5.9 shows the level of agreement of respondent regarding the statement “Dynamic positioning requires a lot of power and the fuel cost is high.” From the table 3.3% of the respondents strongly disagreed with the statement, 4.4% disagreed, 6.7% neither agreed nor disagreed and 24.4% agreed while 61.1% strongly agreed.

Table 5.9: Dynamic positioning requires a lot of power and the fuel cost is high

Dynamic positioning requires a lot of power and the fuel cost is high
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 4 4.4 4.4 7.8
Neither agree nor disagree 6 6.7 6.7 14.4
Agree 22 24.4 24.4 38.9
Strongly Agree 55 61.1 61.1 100.0
Total 90 100.0 100.0

Figure 5.9: Dynamic positioning require a lot of power and the fuel cost is high

 

 

Table 5.10 shows the level of agreement of respondent regarding the statement “Dynamic positioning is vulnerable to electronics and thrusters failure.” From the table 4.4% of the respondents strongly disagreed with the statement, 5.6% disagreed, 7.8% neither agreed nor disagreed and 44.4% agreed while 37.8% strongly agreed.

Table 5.10: Dynamic positioning is vulnerable to electronics and thrusters failure

Dynamic positioning is vulnerable to electronics and thrusters failure
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 4 4.4 4.4 4.4
Disagree 5 5.6 5.6 10.0
Neither agree nor disagree 7 7.8 7.8 17.8
Agree 40 44.4 44.4 62.2
Strongly Agree 34 37.8 37.8 100.0
Total 90 100.0 100.0

Figure 5.10: Dynamic positioning is vulnerable to electronics and thrusters failure

 

 

Table 5.11 shows the level of agreement of respondent regarding the statement “Dynamic positioning system is quite vulnerable to power failure and shortages.” From the table 3.3% of the respondents strongly disagreed with the statement, 6.7% disagreed, 3.3% neither agreed nor disagreed and 38.9% agreed while 47.8% strongly agreed.

Table 5.11: Dynamic positioning system is quite vulnerable to power failure and shortages

Dynamic positioning system is quite vulnerable to power failure and shortages
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 6 6.7 6.7 10.0
Neither agree nor disagree 3 3.3 3.3 13.3
Agree 35 38.9 38.9 52.2
Strongly Agree 43 47.8 47.8 100.0
Total 90 100.0 100.0

Figure 5.11: Dynamic positioning system is quite vulnerable to power failure and shortages

 

 

Table 5.12 shows the level of agreement of respondent regarding the statement “Training on dynamic positioning system is quite expensive.” From the table 3.3% of the respondents strongly disagreed with the statement, 6.7% disagreed, 11.1% neither agreed nor disagreed and 46.7% agreed while 32.2% strongly agreed.

Table 5.12: Training on dynamic positioning system is quite expensive

Training on dynamic positioning system is quite expensive
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 3 3.3 3.3 3.3
Disagree 6 6.7 6.7 10.0
Neither agree nor disagree 10 11.1 11.1 21.1
Agree 42 46.7 46.7 67.8
Strongly Agree 29 32.2 32.2 100.0
Total 90 100.0 100.0

Figure 5.12: Training on dynamic positioning system is quite expensive

 

 

Table 5.13 shows the level of agreement of respondent regarding the statement “Dynamic positioning has high start-up cost.” From the table 5.6% of the respondents strongly disagreed with the statement, 8.9% disagreed, 6.7% neither agreed nor disagreed and 24.4% agreed while 54.4% strongly agreed.

Table 5.13: Dynamic positioning has high start-up cost

Dynamic positioning has high start-up cost
Frequency Percent Valid Percent Cumulative Percent
Valid Strongly disagree 5 5.6 5.6 5.6
Disagree 8 8.9 8.9 14.4
Neither agree nor disagree 6 6.7 6.7 21.1
Agree 22 24.4 24.4 45.6
Strongly Agree 49 54.4 54.4 100.0
Total 90 100.0 100.0

Figure 5.13: Dynamic positioning has high start-up cost

 

 

5.3         CHI-SQUARE TESTS

5.3.1.1                Test 1

To establish the association between “Dynamic positioning has both effectiveness and limitations” and “Dynamic positioning enable the operator to have full control of the vessel,” the researcher conducted a chi-square test for equal proportion and Table 5.14 (Dynamic positioning and control of offshore vessels) and Table 5.15 (Chi-Square Tests) show the findings.

Table 5.14: Dynamic positioning and control of offshore vessels

Dynamic positioning has both effectiveness and limitations * Dynamic positioning enable the operator to have full control of the vessel Crosstabulation
Dynamic positioning enable the operator to have full control of the vessel Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning has both effectiveness and limitations Strongly disagree Count 2 0 1 2 1 6
% of Total 2.2% 0.0% 1.1% 2.2% 1.1% 6.7%
Disagree Count 0 4 0 2 4 10
% of Total 0.0% 4.4% 0.0% 2.2% 4.4% 11.1%
Neither agree nor disagree Count 1 0 1 4 3 9
% of Total 1.1% 0.0% 1.1% 4.4% 3.3% 10.0%
Agree Count 2 2 2 19 3 28
% of Total 2.2% 2.2% 2.2% 21.1% 3.3% 31.1%
Strongly Agree Count 0 5 6 14 12 37
% of Total 0.0% 5.6% 6.7% 15.6% 13.3% 41.1%
Total Count 5 11 10 41 23 90
% of Total 5.6% 12.2% 11.1% 45.6% 25.6% 100.0%

 

Table 5.15 indicates a p value of 0.009, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning and control of offshore vessels. Table 5.14 shows that more than 71% of the respondents who agreed with the statement “Dynamic positioning has both effectiveness and limitations” also agreed, “Dynamic positioning enable the operator to have full control of the vessel.”

Table 5.15: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 32.388a 16 .009
Likelihood Ratio 31.512 16 .012
Linear-by-Linear Association 2.292 1 .130
N of Valid Cases 90
a. 21 cells (84.0%) have expected count less than 5. The minimum expected count is .33.

 

5.3.1.2                Test 2

To establish the association between “Dynamic positioning has both effectiveness and limitations” and “Dynamic positioning system is capable of maintaining required position automatically,” the researcher conducted a chi-square test for equal proportion and Table 5.16 (Chi-Square Tests) and Table 5.17 (Dynamic positioning and maintaining required position automatically) show the findings.

Table 5.16: Chi-Square Tests

Chi-Square Tests
Value df Asymp. Sig. (2-sided)
Pearson Chi-Square 40.010a 16 .001
Likelihood Ratio 28.111 16 .031
Linear-by-Linear Association .027 1 .870
N of Valid Cases 90
a. 20 cells (80.0%) have expected count less than 5. The minimum expected count is .07.

Table 5.16 indicates a p value of 0.001, which is less than 0.05. Since p value is less than 0.05, it implies that there is a significant relationship between dynamic positioning and maintaining required position automatically. Table 5.17 shows that more than 72% of the respondents who agreed with the statement “Dynamic positioning has both effectiveness and limitations” also agreed, “Dynamic positioning system is capable of maintaining required position automatically.”

Table 5.17: Dynamic positioning and maintaining required position automatically

Dynamic positioning has both effectiveness and limitations * Dynamic positioning system is capable of maintaining required position automatically Crosstabulation
Dynamic positioning system is capable of maintaining required position automatically Total
Strongly disagree Disagree Neither agree nor disagree Agree Strongly Agree
Dynamic positioning has both effectiveness and limitations Strongly disagree Count 0 0 0 2 4 6
% of Total 0.0% 0.0% 0.0% 2.2% 4.4% 6.7%
Disagree Count 0 2 0 2 6 10
% of Total 0.0% 2.2% 0.0% 2.2% 6.7% 11.1%
Neither agree nor disagree Count 0 0 4 2 3 9
% of Total 0.0% 0.0% 4.4% 2.2% 3.3% 10.0%
Agree Count 0 0 1 11 16 28
% of Total 0.0% 0.0% 1.1% 12.2% 17.8% 31.1%
Strongly Agree Count 1 2 0 17 17 37
% of Total 1.1% 2.2% 0.0% 18.9% 18.9% 41.1%
Total Count 1 4 5 34 46 90
% of Total 1.1% 4.4% 5.6% 37.8% 51.1% 100.0%

 

 

5.4         SUMMARY

Findings on effectiveness and limitation of dynamic positioning show that most of the respondents agreed that dynamic positioning has considerable effectiveness and limitations. Some of the effectiveness include operator is able to have full control of the vessel and system is capable of maintaining required heading automatically. Limitations include being vulnerable to electronics and thrusters failure and power failure and shortages as well as dynamic positioning has high start-up cost among others.

CHAPTER 6    –     DISCUSSION AND ANALYSIS

6.1         INTRODUCTION

Descriptive survey was employed in the current study to examine effectiveness of dynamic positioning in offshore operations. Closed ended questionnaire was used in this research to collect views and opinions of dynamic positioning operators. The sample size was 90. Analysis of the quantitative data gathered in the study was carried out using descriptive statistical analysis and chi-square test. Majority of the respondents that participated in the research comprising 97.8% were aged 25 years above. Concerning education level, 92.2% of the respondents had bachelor’s degree and above, which shows the respondents were well educated to understand the subject of study on dynamic positioning. Majority of the respondents were male with 68.9%, which could be a pointer to the gender composition in the maritime industry. The designation of the respondents who participated in this research includes senior dynamic positioning operator, dynamic positioning operator, dynamic positioning engineers, dynamic positioning technical officer and vessel operator. This is important because it shows the accuracy of the study since research participants include employees who work with dynamic positioning. Almost all respondents were conversant with the subject of the study as indicated in the findings in Table 3.5.

6.2         Dynamic Positioning

Different aspects of dynamic positioning were investigated in the study in accordance with the research aim. Majority of respondents that participated in this study agreed that dynamic positioning system plays an important role in offshore operations. There are offshore operations, which require that vessels be stationary in deep seas. Maintaining position of a vessel such as equipments and ships used in oil exploration in seas is not easy considering the effect of the waves, current and even wind (Sharit, 2006). However, technological development led to evolution of dynamic positioning system, which tends to address such issues by enabling ship operators to be in control of a vessel against all odds (Vinnem, 2007). Thus, dynamic positioning is very important system in the maritime industry due to the role it plays, which contributes significantly to the global economy. The researcher also established as indicated in the findings that dynamic positioning enables offshore vessels to stay in position (Berntsen, 2008). One of the roles dynamic positioning plays is to make offshore vessels to stay in the desired positions, which is very significant when undertaking some of the offshore operation such as exploration (Liu, 2007).

Majority of the respondents also agreed that dynamic positioning uses computer technologies to overcome changes in the location of offshore vessels and that dynamic positioning system prevents the impact of current, wind, wave acting on the ship (Han, 2005). Dynamic positioning is a product of technological development aimed to addressing serious problems in offshore operation. The impact of wind, current and wave in deep sea can be quite difficult to deal with but with the emergence of dynamic positioning, impact of wave, currents and wind can be contained to the benefit of the economy since the use of the system saves a lot of resources. In addition, majority of the respondents agreed that dynamic positioning allows greater manoeuvring flexibility, which was not possible with other systems (Mills, 2005). The investigator further established that dynamic positioning is advantageous compared to other systems like Jack-up barge and spread mooring to anchor pattern. Unlike Jack-up barge and spread mooring, dynamic positioning is capable of reacting to weather changes apart from being able to adapt to operation requirements. This means that the contribution of dynamic positioning in the maritime industry is quite significant (Fenton and Neil, 2013). Furthermore, most of the respondents indicated that the use of dynamic positioning system comes with less risk for environment since it does not cause mooring line on the seabed.

6.3         Benefits of Dynamic Positioning

The current study investigated the benefits attributed to dynamic positioning. Majority of the respondents agreed that dynamic positioning helps in increasing demand for oil and gas exploitation in deep sea (IMCA, 2010). One of the major challenges that faced oil exploitation in deep seas was ability to hold offshore vessels in required position but with the advent of dynamic positioning, oil explorer can therefore use dynamic positioning system to undertake oil exploitation with ease. Majority of the respondents also agreed that dynamic positioning has many important benefits in Maritime industry, which include saving time and increasing global economic growth (Kristiansen, 2005). Dynamic positioning system helps in keeping offshore vessel in the required position within relatively short time saves time. On the other hand, since dynamic positioning has significantly contributed in increasing demand of sea oil exploration, this in turn has contributed greatly to the growth global economy. Dynamic positioning system is not dependent on water depth and other systems, which makes it quite important and effective in offshore operations (Nguyen and Sørensen, 2009). For instance, a company can now exploit oil in very deep seas with no or little failure. Majority of the respondents also agreed that dynamic positioning allows quick set up and that dynamic positioning is not limited by obstructed seabed, as is the case with other systems. Moreover, the researcher established that dynamic positioning does not need anchor handling tugs. Most of the dynamic positioning operators and managers agreed that dynamic positioning saves money through low fuel cost among other factors (Jian, 2009). Compared to the role it plays, dynamic positioning is beneficial in cost saving since it uses relative low. In addition, dynamic positioning saves money due to no expenditure on tugboats and that dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces.

6.4         Limitations and Effectiveness of Dynamic Positioning

Most of the respondents that participated in the current study indicated that dynamic positioning has both effectiveness and limitations. Majority of the respondents agreed that dynamic positioning enables the operator to have full control of the vessel (Mills, 2006). This is very important in undertaking offshore operation such as exploration and oil exploitations among others. Being in control of offshore vessel against strong agents of nature like wind, current and waves is a great positive effect of dynamic positioning. The technology can therefore be used to enhance productivity in offshore maritime activities (Faulkner, 2000). In addition, majority of the respondents agreed that dynamic positioning system is capable of maintaining required heading automatically as well as being capable of maintaining required position automatically. These are attributes of performance of dynamic positioning, which makes it essential and key tool to have in offshore vessels. Dynamic positioning system does not only make the system operators to be in control of offshore vessels but majority of the respondents said that dynamic positioning can also be used in situations where a lot of precision is needed (Fang and Blanke, 2011). Most of the offshore activities in seas require precision in order to save both time and resources and dynamic positioning is the solution that they need to achieve such goal.

Concerning whether dynamic positioning can be used on locations where other systems cannot be applied, more than 83% of the respondents agreed that indeed dynamic positioning could be used on locations where other systems cannot be applied. Such attributed of dynamic positioning does makes it a unique product of computer technology, which offers solutions which previous system, could not address. Operation and management of dynamic positioning system as indicated by majority of the respondent, requires highly educated staff members. Technology is good and effective but they cannot operate on their own. Human is one of the most important resources that entities use to gain competitive advantage as well as to drive the industry. Technology is therefore as good as its users (Shi, Phillips and Martinez, 2005). Operation of dynamic positioning systems therefore need skilled and experience employees that understand the technology competently. It is only when competent staff operate dynamic positioning system that its benefits can be realized accordingly. Dynamic positioning requires position reference continuously as observed indicated by most of the respondents. Besides, dynamic positioning requires a lot of power and the fuel cost is high (Fossen, 2002). Other limitations of dynamic positioning include the fact that dynamic positioning is vulnerable to electronics and thrusters failure; dynamic positioning system is quite vulnerable to power failure and shortages, and high cost of training on dynamic positioning system. Majority of the respondents also agreed that dynamic positioning has high start-up cost

6.5         SUMMARY

Dynamic positioning system is very effective in their use in offshore vessel. However, the investigators established that dynamic positioning has both effectiveness and limitations. Dynamic positioning is very effective in the sense that operator can use it to have full control of the vessel irrespective of the depth of the sea, which makes it better that other systems in the industry. The findings indicate that dynamic positioning is vulnerable to electronics and thrusters failure. Moreover, dynamic positioning system is quite vulnerable to power failure and shortages, and it has high start-up cost, which are significant limitations.

 

CHAPTER 7    –     CONCLUSION AND REFLECTION

The purpose of this study was to examine effectiveness of dynamic positioning in offshore operations. The objectives of this research included evaluating the need for dynamic positioning in offshore operations, to review the existing publications on dynamic positioning classes, techniques and systems, to discuss the benefits of dynamic positioning of the vessel in offshore operations and to assess the limitations of dynamic positioning systems. The researcher used descriptive statistical analysis where closed ended questionnaire was used to collect opinions and views of respondents. The respondents were operators of dynamic positioning system. Statistical methods such as chi-square test and descriptive statistical analysis was used in the data analysis. Most of the respondents that participated in the study were aged over 24 years and they had at least a bachelor’s degree.

Dynamic positioning plays a very important role in controlling offshore vessels, which makes it a requirement in offshore operations. For instance, dynamic positioning was established to have greatly contributed to demand for oil and gas exploitation in deep sea, making it a very important tool in the maritime industry with respect to offshore operations. There are several benefits attributed to the use of dynamic positioning in offshore operations, which makes it an important necessity. Some of the benefits of dynamic positioning include the fact that dynamic positioning system is not dependent on water depth, the system saves time, dynamic positioning is not limited by obstructed seabed and that dynamic positioning system enables the operator to have full control of the vessel. Other benefits include ability of dynamic positioning system to maintain required position and heading automatically, dynamic positioning can be used in situations where a lot of precision is needed, the system saves money through low fuel cost among other factors and the fact that the use of dynamic positioning saves money due to no expenditure on tugboats. The findings of this study indicate limitations of dynamic positioning include vulnerability of dynamic system to electronics and thrusters failure, power failure and power shortages. Moreover, the findings indicate that dynamic positioning has high start-up cost and the system requires highly educated staff members to manage and operate.

The whole research on effectiveness of dynamic positioning in offshore operations was undertaken successfully. The research activities of this research include review of past studies, primary data collection, sampling, data collection, data analysis and final report rewriting. The researcher considered all research activities and accorded every activity the needed attention. Research activities influence validity and reliability of a research as ascertained by the investigator. Primary data collection is quite cumbersome and requires a lot of resources and time. Therefore based on the timeframe within which the study to be concluded, primary data was collected from only 90 respondents from 15 marine companies otherwise data could have been gathered from more than 1000 respondents from across the global maritime industry. Constant consultation of the project supervisor was crucial for the successful completion of this research.

 

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APPENDIX A     Survey Questionnaire

The effectiveness of dynamic positioning in offshore operations

Dear Respondent,

Thank you for agreeing to participate in this research into effectiveness of dynamic positioning in offshore operations. I am undertaking this research as a part of my Master degree programme of studies for the University.  This academic survey asks for your HONEST responses with regard to every section of the questionnaire. Since this is an academic survey, your views in the survey will be held private and used only for purposes of achieving the study aim and objectives. Hence, your personal details will remain anonymous and will not be disclosed to any third party. In addition, when the research is completed, your responses will be destroyed.

            SECTION 1: DEMOGRAPHIC AND GENERAL WORK INFORMATION

  General Information (Please Select the Appropriate Choice by Marking One Check-Box)
1.     Age:

<18 years   18-24 years            25-34 years           35-40 years          40-60 years

2.     Education Level:

O/A-Level     Diploma            Bachelor’s degree       Master’s degree        Doctorate degree

3.     Gender:

Male                         Female

4.    Work Designation:

Senior Dynamic Positioning Operator       Dynamic Positioning Operator

Dynamic Positioning Engineer        Dynamic Positioning Technical officer

Vessel Operator

 

SECTION 2: WORK EXPERIENCE AND KNOWLEDGE OF ISSUE

  1. Do you regard yourself as being familiar with the subject of the effectiveness of dynamic positioning in offshore operations?

 

Strongly Disagree           Disagree  Neither Agree nor Disagree  Agree  Strongly Agree

 

The following series of questions ask you to indicate how much you agree or disagree with a particular statement about productivity. Please kindly mark only one answer, which best shows your degree of agreement or disagreement with the statements set out below.

Strongly Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
Dynamic Positioning
6.    Dynamic positioning system plays an important role in offshore operations Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
7.    Dynamic positioning enables offshore vessels to stay in position Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
8.    Dynamic positioning uses computer technologies to overcome changes in the location of offshore vessels Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
9.    Dynamic positioning system prevents the impact of current, wind, wave acting on the ship Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
10. Dynamic positioning allows greater manoeuvring flexibility Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
11. Dynamic positioning is advantageous compared to other systems like Jack-up barge and spread mooring to anchor pattern Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
12. Dynamic positioning system is capable of reacting to weather changes Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
13. Dynamic positioning is able to adapt to operation requirements Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
14. The use of dynamic positioning system comes with less risk for environment since it does not cause mooring line on the seabed Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
BENEFITS OF DYNAMIC POSITIONING
15. Dynamic positioning helps in increasing demand for oil and gas exploitation in deep sea Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
16. Dynamic positioning has many important benefits in Maritime industry Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
17. Dynamic positioning has contributed in increasing global economic growth Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
18. Dynamic positioning saves time Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
19. Dynamic positioning system is not dependent on water depth Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
20. Dynamic positioning allows quick set up Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
21. Dynamic positioning is not limited by obstructed seabed Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
22. Dynamic positioning does not need anchor handling tugs Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
23. Dynamic positioning saves money through low fuel cost among other factors Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
24. Dynamic positioning saves money due to no expenditure on tugboats Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
25. Dynamic positioning can save power since it is capable of calculating the power it needs to overcome external forces Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
Effectiveness and Limitations of Dynamic Positioning
26. Dynamic positioning has both effectiveness and limitations Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
27. Dynamic positioning enables the operator to have full control of the vessel Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
28. Dynamic positioning system is capable of maintaining required heading automatically Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
29. Dynamic positioning system is capable of maintaining required position automatically Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
30. Dynamic positioning can be used in situations where a lot of precision is needed Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
31. Dynamic positioning can be used on locations where other systems cannot be applied Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
32. Operating dynamic positioning requires highly educated staff members Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
33. Dynamic positioning requires position reference continuously Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
34. Dynamic positioning requires a lot of power and the fuel cost is high Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
35. Dynamic positioning is vulnerable to electronics and thrusters failure Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
36. Dynamic positioning system is quite vulnerable to power failure and shortages Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
37. Training on dynamic positioning system is quite expensive Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree
38. Dynamic positioning has high start-up cost Strong Disagree Disagree Neither Agree nor Disagree Agree Strongly Agree

 

THANK YOU FOR YOUR COOPERATION IN MAKING THIS SURVEY A SUCCESS

 

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