Posted: December 25th, 2023
Impact of Ship Collision on the Marine Environment
Impact of Ship Collision on the Marine Environment
1. Introduction
Ships are designed to be used in the water, whether it be on seas, rivers or lakes, therefore their most likely collision partner are other ships. From the cost of human lives and injuries to the monetary amount of damage and repairs, collisions have proven to be a dangerous and expensive accident in the maritime industry. In fact, ship collisions ranked the number two most common accident involving ships of 100 gross tons or more, from the year 1992 to 2002, right behind that of allisions. The cost of collision repairs can vary depending on the types of ships involved, where the damage occurred and the extent of the damage. Cost can be in the excess of hundreds of thousands to millions of dollars, all paid by the responsible ship owner. This is similarly compared to that of harmful oil spills that have occurred in the marine environment.
From the case of the oil tanker Prestige (2002) where the ship was fractured in half by rough seas after being denied entry to a port of refuge by the French and Spanish governments. The tanker eventually sunk on November 19, 2002, releasing over 77,000 tonnes of heavy fuel oil that caused extensive damage to the Spanish and French coastlines, as well as to the Bay of Biscay. This alone amount underlines the intensity and danger of ships when there is a collision in the marine environment. With oil being the most harmful substance to the marine environment, there have been many cases where collisions have punctured oil tanks on ships or have caused the rupturing of oil platforms, resulting in large oil spills and damage to the marine environment. An example of this would be the Torrey Canyon where in 1967 an oil tanker ran aground off the coast of Cornwall, England and caused Britain’s worst ever environmental disaster at the time. This has created a huge demand and awareness for the prevention of pollution and protection of the marine environment from ship accidents, with severe regulations and repercussions for those responsible for damaging the environment.
1.1 Background of Ship Collisions
The majority of past research has been focused on response and cleanup technology, while the research of impacts on the environment has been largely theoretical and speculative. A topic by Taylor and Grubb supports this statement, mentioning how the results of various spills and accidents are often used for case study scenarios in the development of oil spill response technology, while the actual impacts of the spills are difficult to assess since they may be episodic and of a chronic nature. This indicates the impacts of ship accidents have not been fully understood. An understanding of shipping safety can be obtained through the study of the circumstances and the environment in which accidents often occur. Identification of areas and types of shipping accidents can be used to assess risks and to implement preventative measures to reduce the chances of accidents occurring. This would lead to improved safety and less damages to the environment in the event of a shipping accident.
Ship collision is one of the major maritime disasters that has threatened the safety and economic vitality of maritime nations since the beginning of international shipping. Shipping is an essential and efficient mode of transportation for the carriage of goods and services through the vast expanse of the world. The increased demand and reliance on oil has resulted in a corresponding increase in oil transportation. Studies have shown that the expected growing trend of oil transportation will eventually lead to an increase in oil spills, with collisions being the major contributor of such spills. This has led to a great concern of the safety of shipping, and in particular, the impacts of ship collisions on the environment. Although major accidents and oil spills such as the grounding of the Torrey Canyon in 1967 and the Exxon Valdez in 1989 have provided evidence of the severe damage to the environment caused by ship groundings and collisions, there has been relatively little research and analysis aimed at investigating the impacts and damages caused by these accidents.
1.2 Significance of the Marine Environment
To develop effective measures and to assess the most appropriate response to ship-sourced pollution, decision-makers need to know the likely effects of the pollution and the scale of the damage. This enables cost-effective decisions to be made to aid restoration, rehabilitate the environment, and compensate those affected by the pollution. An effective way to predict the fate, effects, damage, and scale of damage of a potential pollution incident is to assess similar past incidents and simulate the event in a research facility. Information gathered from this type of research can be critical in understanding the implications of conventions and potential policy decisions and is a more effective way to influence environmentally sound behavior in the shipping industry than the force of the incident. This type of research is essentially what we have conducted in relation to the New Carissa incident in Oregon, USA, and the Kermadec event in New Zealand.
Marine transportation is a critical element in the global economy. Almost 80 percent of global trade by volume is carried by sea, and the volume of seaborne trade is expected to double between 1996 and 2015. This has led to an increase in the size and number of vessels and further dependency on the marine environment. Coupled with the fact that the majority of oil is found in developing nations and transported to developed nations, it means that there is a high quantity of oil being transported through marine areas that are ecologically and biologically significant. All these factors increase the potential for marine pollution caused by ship-sourced oil and other hazardous substances. Although prevention is the best option, post-incident measures after an oil spill or marine debris event are critical.
1.3 Purpose and Scope of the Thesis
The major purpose of this project is to highlight the impact of ship collision on the marine environment. This can be further broken down into three objectives.
The first is to identify and describe contributory factors that lead to the occurrence of ship collision. It is important to ensure that all root causes are pinpointed rather than just the immediate cause of the collision.
This is because the identification of all possible causes of ship collision can help in the development of a more effective safety culture within the shipping industry.
The second is to assess the extent of damage caused by the collision to the environment. In order to do this, there is a need to compare and contrast the difference in damage when the type of ship involved ranges from a small one such as a fishing vessel or a domestic coaster, to a large one such as an oil tanker or container ship. The damage caused by the former would likely be negligible when compared to the latter. This is because the larger ship has a higher mass and would likely be traveling at a higher speed, hence the energy released during the course of the collision is greater. A case in point is the 2008 collision between the MV Waily and a Chinese oil tanker in Singapore. A subsequent study that was conducted showed that the level of damage to the marine environment was significantly higher than if it were a collision between two smaller ships at a different location.
2. Causes of Ship Collisions
Human factors refer to causes attributable to the personnel involved in an incident and can be subdivided further into active errors and latent conditions. Active errors are direct unsafe acts, which often have an immediate adverse effect, for example, a tired bridge watchkeeper falling asleep on duty resulting in a grounding. Latent conditions tend to be less obvious and develop over a long period of time within the organization, often at the management level. They may lie dormant for many years before combining with active failures and producing an accident. Often there is no single direct cause of an accident and to understand how it occurred one must consider the “Swiss Cheese Model” (Reason, 1990). This model suggests that with regards to accident causation, the “holes” in the cheese slices are the latent conditions and the active failures are the passage of an accident through the holes in the slices, where defenses have failed. Reason covers a wide range of human factors in his model including personnel fatigue, pressure, and stress, poor communication between crew members, and inadequate training and has shown how all can directly cause accidents. Consideration of Reason’s model and range of human factors has shown how it can be applied to marine accidents with a study by Parry and Salmon using it to analyze the loss of the cargo MV Derbyshire (Parry and Salmon). A further study by Mearns and Yule (Mearns and Yule, 2004) has investigated into levels of job-related stress for UK seafarers as well as the relationship between unsafe acts and accidents.
2.1 Human Factors
Studies carried out by marine safety instructors and government organizations overwhelmingly indicate that human error is the primary and most fundamental cause of maritime casualties. The large increase in the size of vessels navigating the world’s oceans over the past few decades has not been matched by a comparable increase in seamanship skills or basic understanding of the principles of shiphandling. This has been brought about largely due to a decrease in educational standards within the shipping industry, coupled with an increase in the reliance on technology and electronic aids to navigation as a means of promoting safety at sea. Despite the fact that the technology utilized on board modern vessels has improved by leaps and bounds, a large percentage of navigational watch keepers do not have a proper understanding of how the equipment they use actually works, nor are they often capable of maintaining the equipment in good working order. Consequently, they will sometimes have a misplaced faith in the reliability of their electronic aids to navigation and may not have a sufficient understanding of traditional methods of navigation as a means of cross-checking the accuracy of their electronic fixes.
The “over professionalization” of shipboard management in today’s world has meant that there is often an undue amount of pressure placed upon ship’s officers by shore-based management as well as the charterers of the vessel, to carry out certain tasks within an unrealistic timeframe. This is with the underlying notion that faster turnaround of cargo equates to increased profitability for the shipping company. Such factors have often contributed to fatigue and a subsequent lack of proper rest and meal periods for ship’s officers, all of which has a negative impact on their ability to perform their duties safely and effectively. Join this with unfeasible scheduling and busy traffic in and out of port areas and the chances of a collision happening at some stage are significantly increased. Collectively, the aforementioned factors are the various ways in which the human element brings about ship collisions.
2.1.1 Crew Fatigue
2.1.2 Navigation Errors
2.1.3 Communication Failures
2.2 Environmental Factors
Immediate “wear and tear” on oceanographic conditions in an area often presents an accurate picture of the effects of ship-sourced pollution on the marine environment. The most chronic effect is an alteration in the behavior of affected species. Changes in behavior range from mild effects, such as those seen in sublethal effects on growth and reproduction, to more drastic effects, such as a species becoming locally extinct. Large spills can have a range of effects. For example, the 2002 Prestige oil spill off the coast of Spain and the 1989 Exxon Valdez oil spill have caused the complete eradication of some species. The Amoco Cadiz ran aground in 1978 on Portsall Rocks off the coast of Brittany, France, split in two and discharged 220,000 tons of crude oil that devastated the local environment.
The introduction of alien species has occurred when substances released from damaged ships have caused ecosystem disturbance. An example of this occurred in Australia when the anti-fouling agent tributyltin, which is toxic to marine life, led to a strong decrease in populations of the dogwhelk. Tributyltin has also been linked to abnormalities in dogwhelks, causing an increase in females and imposex in which females acquire male sexual characteristics. In Japan, the use of the same anti-fouling agent has caused a decrease in populations of 47 marine species.
2.2.1 Weather Conditions
2.2.2 Visibility Issues
2.2.3 Natural Hazards
3. Consequences of Ship Collisions
Oil spills damage coastal habitats such as salt marshes and mangroves by killing plants and preventing the germination of seeds. Oil can persist in sediments for many years and act as a source of contamination for marine organisms. Long-term impacts can include changes in community structure and loss of habitats that were nurseries or spawning grounds for fish and invertebrates. Ecosystem recovery is highly variable and can take many years. The Exxon Valdez oil spill in Alaska in 1989 is an example of how the effects of a large spill can be long-lasting and, in some cases, permanent. This tragic event provides a wealth of information on the impacts of oil spills and is still being used to improve oil spill response techniques today.
The primary impact from a ship collision is the release of oil into the marine environment, resulting in pollution. Oil spills can have wide-ranging impacts, and there is no “one size fits all” response as the effects are dependent on a variety of factors. Different types of oil behave differently in the marine environment and have different toxic properties. Heavy oils can smother and kill organisms, particularly those living on or in the seafloor. Lighter oils can be highly toxic and have more serious impacts on a wider range of organisms. Floating oil can impact birds by causing matting of feathers and habitat destruction. Effects on marine mammals can be severe, with reports of dolphins and whales suffocating after surfacing through oil slicks. Contact with oil can have sublethal effects on organisms, such as reduced growth and reproductive rates. In addition to the damage caused by the oil itself, control measures used during and after a spill can also impact the environment. The use of dispersants can result in the formation of toxic oil-in-water emulsions, and prolonged monitoring and assessment attempts can divert resources from conservation and research.
3.1 Oil Spills and Pollution
Many impacts occur when a ship has collided with another vessel or a stationary object. The most significant of these is an oil spill. The resulting impact of oil spills on the marine environment and its ecology has been the focus of a vast amount of empirical research. It is now commonly accepted that oil spills can have a devastating impact. The aftermath of a spill can persist in the marine environment for decades. One only has to consider the case of the Exxon Valdez supertanker which ran aground on Bligh Reef, Alaska in 1989. Even now, 17 years after the event, oil can still be found on the beaches of the Prince William Sound. An oil spill can also have an impact on all habitats and ecosystems within the marine environment, from sea to shining sea. Oil spilled at sea is known to travel vast distances on the currents and can come ashore far from the original spill site, as seen in the case of the Sea Empress which polluted over 200 km of Welsh coastline. Oil may also become submerged, damaging deep sea habitats and the organisms which dwell there. This can make clean-up operations difficult as not all impacts may be observable and damage to some ecosystems may be irreversible. A large body of research exists on the impacts of oil on specific marine organisms and the toxicity and longevity of the effects can vary from species to species. Some of the long-term effects of oil spills can continue to impact the environment many years after the event and as such are difficult to study. It is widely recognised that oil is an extremely toxic substance and can cause mortality in many organisms if they are exposed to sufficiently high doses. As oil is essentially a hydrocarbon, a substance foreign to the aquatic environment, it has the potential to cause profound and varied physical and physiological effects in exposed organisms. In general, the effects of oil on an organism can be divided into two phases: the acute and chronic. Duration and extent of exposure and the concentration and type of oil are factors which dictate which phase an organism will pass through. During the acute phase, the oil may cause death through suffocation and ingestion in organisms such as fish and shellfish. For marine birds, oiling is often fatal. Studies have shown that as little as 1 ml of oil can kill a seabird. High-profile events such as the oiling of penguins in the Treasure oil spill in South Africa have increased public awareness of the impacts of oil on marine birds. Should an organism survive the acute phase, it may still suffer chronic effects from oil which can in some cases be worse than the acute effects. These effects can include immunosuppression, reproductive failure, and developmental abnormalities. The long-term population effects on some species from oil spills are still unknown.
3.1.1 Environmental Impact
3.1.2 Effects on Marine Life
3.1.3 Economic Consequences
3.2 Damage to Maritime Infrastructure
Tourism is also a very lucrative industry that some countries rely on for economic stability. The natural beauty of an area and its beaches are often the main attraction for tourists. Any perception of damage can jeopardize future tourist industries. Usually, it is the threat of contamination that will keep tourists away from affected beaches, and even small oiling incidents have caused a significant reduction in tourism revenues. For example, the summer tourists along the North Adriatic coast of Italy bring in an estimated $940 million per year. In 1993, a tanker accident offshore of Trieste resulted in approximately 80km of shoreline being oiled. The tourist industry in this area reported losses ranging from 6-50%, totaling an estimated $200 million for the single season.
I mentioned earlier that approximately 80% of world trade is carried by sea. This trade is vital to a country’s economy and requires the use of ports to bridge the gap between sea and land. This is especially important for small island developing states that rely almost entirely on imported goods. Ports are often located in coastal areas, which are environmentally sensitive. Any damage caused to the port environment can be costly and sometimes impossible to repair. Damage can occur to port facilities by ship groundings or anchorings, or through direct damage from oil contamination. Direct and indirect oil damage to coastal facilities has included the corrosion of pilings, increased maintenance dredging, decreased property values, and even abandonment of the area because of the high cost of rehabilitation.
3.2.1 Port Facilities
3.2.2 Coastal Structures
3.2.3 Navigation Aids
4. Mitigation Strategies
The most notable efforts are the creation of a series of traffic separation schemes and two differing in design to reduce the likelihood of incidents in the GBR. The Torres Strait Traffic Separation Scheme has greatly reduced the risk of collisions in a high traffic zone. A risk analysis conducted prior to its introduction, involving investigation of the area’s marine traffic density, types of vessels, and direct observation of their movements. The analysis identified that the proposal of a two-way route for the safest navigation of all vessel types was the most effective way to reduce collision risks.
The most significant step in the prevention of ship collisions is International Maritime Organization resolutions A.285 and A.678 (IMO). A.285 is the “revised guidelines for the maintenance of minimum safe navigational clearance distance” and A.678 is the “code for the reduction of the hazards of collision”. These guidelines are in relation to various regulations set down in “The International Regulations for Preventing Collisions at Sea 1972” and are in regards to providing clear guidelines towards traffic separation schemes, shipping lanes, and the creation of no-ship zones around hazardous coastal areas, such as the IMO created Particularly Sensitive Sea Areas.
Mitigation can be defined as the deliberate actions to reduce adverse impacts by controlling sources, reducing the pathways, or by modifying the adverse impact, often in order to protect human health or the environment. This is an important step following the analysis of the aforementioned impacts, and much work has been done in the way of preventing collisions and minimizing their environmental effects.
4.1 International Regulations and Standards
There is relatively little a country can do to extend the geographical boundaries within which it can claim legal jurisdiction. However, a coastal state can extend its influence to both the territorial sea and areas beyond national jurisdiction by taking a more active role in maritime affairs. Maritime law encompasses the jurisdiction of flags, coastal states and port states as well as that of international organizations, and its legislation has an impact both on the effectiveness of mitigation strategies and on the prevention of a collision occurring. The nature of the impact varies depending on the specific regulations and standards that are being enforced, and can be positive or negative. For example, the prevalence of substandard ships, typically flying flags of states where they are not actually registered, can be combated by unilateral measures regulating the quality of ships that are allowed to enter a certain state’s port or even a regional port state control agreement. This will reduce the risk of a collision occurring and consequently lessen its effects on the marine environment. On the other hand, a regulation designed to protect the marine environment, such as the recent International Maritime Organization’s (IMO) introduction of a sulfur emission cap, can have unintended negative effects on the safety of ships. The sulfur cap has led to an increase in the use of cheaper, more viscous fuels that are thought to pose an increased navigational risk due to a higher likelihood of machinery failure and a slower speed of response to situations that may lead to a collision.
4.1.1 IMO Conventions
4.1.2 Safety Measures
4.2 Technological Advancements
There are many technological advancements that can be used to detect and identify oil from ships. One of these is the use of Synthetic Aperture Radars in satellite technology. Together with in situ sampling, these devices can provide information which can be used to estimate the volume of oil which an oil spill has caused. This is because the radars provide data from which an algorithm can be run which will provide an estimation of the volume of oil. Also, as these devices have a large area of coverage and are unaffected by adverse weather, they are ideal for providing information for the detection of accidental discharges and illegal discharges at sea. Although it is mainly used to detect oil pollution, another satellite technology known as AIS (Automatic Identification System) can also be a useful deterrent for preventing pollution. This is because the system provides detailed information about ships including their identity, position, and the time at which this information is accurate. If satellite tracking evidence revealed that a ship illegally discharged oil or another pollutant, this information from the AIS could also be used to link a specific pollution event with a specific ship. This can be particularly useful for holding polluters accountable for their actions.
4.2.1 Collision Avoidance Systems
4.2.2 Vessel Traffic Services