IMPACT OF TANK CONSTRUCTION ON CORROSION OF SHIP BALLAST

Introduction
Corrosion is a major cause of marine structural failures. Corrosion results in loss of structural strength at local and global levels, and leads to fatigue failure and stress corrosion cracking. Some recent marine incidents with tankers have been directly linked to accelerated corrosion [7]. Localized corrosion is among the major types of physical defects found largely on ship structures. The areas of the ship most susceptible to corrosion are the ballast tanks owing to the intense contact with seawater on both the sides, humidity, and the chloride-rich environment, even when empty. Because of the double hull configuration required by the Oil Pollution Act of 1990 [6–9], ballast tanks are difficult to maintain.
The access is limited and the environment is unfriendly, the light is scarce, large parts are hard to reach, and the cost of decent maintenance is towering high, mainly because the working conditions are troublesome. In short, double hull ballast tanks act as the Achilles’ heel of the ship.
The introduction of the double hull tankers in the nineties relocated all the structural elements from the cargo into the ballast tanks [7]. This configuration aggravates the corrosion problem on board. The quantity of corrosion in ballast tanks is therefore a decisive factor for ending the economic life of the ship and sending her to the scrap yard [10].
Today, ship’s ballast tanks are constructed in grade A steel and protected with a standard epoxy coating and sacrificial zinc anodes at some locations. These serve to reduce and in some instances effectively defer corrosion and mitigate corrosion consequences [5]. Such a construction has been applied without significant alterations for decades. However, the goal of this study is to compare this traditional approach with some feasible alternatives through an analysis of the total cost, restricted to construction, exploitation and maintenance of the ballast tanks, hereinafter called total cost of ballast tanks (TCB). As such, the impact of any structural investments can be investigated in the conceptual stage of the vessel. Important elements in such an analysis are the design of the tank and the selection of appropriate construction, equipment and protection material.
Table of Contents
CHAPTER ONE: INTRODUCTION
1.1 Background of the Study
1.2 Statement of the Problem
1.3 Purpose of the Study
1.4 Significance of the Study
1.5 Research Questions
1.6 Delimitations of the Study
1.7 Limitation of the study
CHAPTER TWO: REVIEW OF RELATED LITERATURE
2.0 Review of Related Literature
2.2 Empirical Studies
2.3 Theoretical Framework
CHAPTER THREE: RESEARCH METHOD
3.1 Introduction
3.2 Area of the Study
3.3 Research Design
3.4 Population of the Study
3.5 Sample and Sampling Technique
3.6 Research Instrument
3.7 Validation of the Instrument
3.8 Data Collection Technique
3.9 Data Analysis Technique
CHAPTER FOUR: DATA PRESENTATION, ANALYSIS
AND DISCUSSION
4.1 Introduction
4.2 Data Presentation
4.3 Discussion of Findings
CHAPTER FIVE: SUMMARY, CONCLUSION AND
RECOMMENDATIONS
5.1 Introduction
5.1 Restatement of the Problem
5.2 Summary of Findings
5.3 Conclusion
5.4 Recommendations
5.5 Suggestions for Further Research
References
Appendix