Ship collision damages: Case studies

FPSOs have a risk profile different from fixed platforms and commercial trading tankers. Being stationed in one location and routinely visited by supply boats and shuttle tankers. FPSOs can be collided by these ships. In addition, passing ships also pose a collision risk if an FPSO is close to a sailing route. This paper presents a systematic approach to address the risk of collision and contact damage. It is aimed to propose a framework that can be applied in structural designs and risk assessment schemes. The focus is placed on accident scenarios, evaluation approaches and acceptance criteria, the three major issues for a risk assessment and also for a relevant design standard. Accident scenarios and the associated occurrence frequency may be determined through statistics from historical data, expert opinions, and risk analysis, depending on different situations. A spectrum of tools has been developed in recent years that predicts the structural damage of collisions, including simple formulae, simplified analytical methods, simplified FEM, and non-linear FEM simulations. Those based on the advanced structural crashworthiness theory provide powerful and practical tools, and are well suited for design evaluations and risk analysis. Contact damage is more likely to occur than accidents resulting in rupture of shell plating. However, this type of accident has received very limited attention. An analytical approach is presented for analyzing contact damage that can be used during earlier design stage. Acceptance criteria for collision and contact accidents are discussed. The emphasis is on structural integrity including local strength and hull performance. Introduction FPSOs have a risk profile different from fixed platforms and commercial trading tankers. Being stationed in one location and routinely visited by supply boats and shuttle tankers. FPSOs can be collided by these ships. In addition, passing ships also pose a collision risk if an FPSO is close to a sailing route. A collision accident can lead to costly consequences in loss of lives, damage to property and/or environment. As past accidents have demonstrated, the indirect cost of compensation and bad publicity can be even higher. This has been the driving force in recent years for developing standards for design against collision accidents for trading oil tankers. A collision with low kinetic energy can result in permanent deformations of side structures instead of rupture of side shell. This low-energy collision is sometimes called "contact accident". Usually, contact damage is not catastrophic and does not pose a threat to the safety of the installation and the protection of environment. Contact damage receives little attention. This paper presents a systematic approach to address the risk of collision and contact damage. It proposes a framework that can be applied in structural design and risk assessment. Discussion is given to accident scenarios and acceptance criteria.

With the development of society, international trade is playing an important role. Maritime transport has become the main mode of transport in international trade with its advantages of low transport price, large transport volume and low environmental pollution. However, the rapid development of maritime transport is accompanied by the risk of maritime accidents. Studies show that ship collision accident has always been the main type of maritime accidents, and ship collision caused by human factors accounts for more than 90% of the total accidents. It has become a key issue in the research field of ship navigation safety to analyze the causes of ship collision and explore the mechanism of human factors. By analyzing the ship collision accident reports, this paper summarizing the main human factors of ship collision, and through analyzing the causal chain of ship collision accident to determine the Bayesian network structure. Finally, this paper using the accident reports into the model to illustrate the effectiveness of the Bayesian network model; meanwhile, by analyzing the cause of the Bayesian network model, this paper gets most likely cause chain that cause collision accident happens, so as to providing safety management countermeasures for the crew, ship company and ship safety management department.

ABSTRACTOn 16 January 2015, about 10 miles east of Busan, South Korea, Liberian container carrier, M/V Ernest Hemingway collided with Korean fishing boat, Geunyang-ho, and Geunyang-ho sank and two Korean nationals perished and about 600 liters of fuel oil on board Geunyang-ho spilt into the sea. M/V Ernest Hemingway’s crew escaped from the site without carrying out duties of rescue after the collision. The Busan District Prosecutor’s Office arrested and prosecuted M/V Hemingway’s second officer and an able seaman, Philippine nationals, for the criminal facts subject to judgement, violation of the Act on Aggravated Punishment, etc., of Specific Crimes, Professional Negligence resulting in ship sinking, and violation of the Marine Environment Management Act. Busan District Court pleaded guilty and sentenced fine for the violation of the Marine Environment Management Act, on the other hand, sentenced dismissal of public prosecution for the violation of the Act on Aggravated Punishment, etc., of Specific Crimes and professional negligence resulting in ship sinking due to lack of jurisdiction based on UNCLOS Article 97(1). Looking at the rulings and the annotations on this case, the main issues were whether South Korea has jurisdiction on ship collision incidents on the high seas as the state of the alleged victim’s nationality, and whether South Korea may exercise criminal jurisdiction over marine pollution caused by a ship collision on the high seas. This paper examines the decisions by the Courts and the main issues related with the case. Here is a summary of what has been reviewed in this paper: First, UNCLOS Article 97(1) is applicable for all criminal penalties of the captain and crew members concerning ship collision and other navigational accidents, without consideration on the intention, and can also be applied to intentions or attempts of illegal activities. Therefore, it can be applied to the events causing loss of life or serious injury (professional negligence resulting in deaths, running away after professional negligence resulting in deaths, etc.) and physical damage (professional negligence resulting in ship sinking, or ship damage, etc.) that were caused by ship collision, allowing priority over criminal jurisdiction exercised by the flag state and the state of the alleged offender’s nationality. Second, it is appropriate to interpret that the exclusive jurisdiction of the flag state on high seas as having a superior position against the jurisdiction of other states, not as having jurisdiction that excludes all other states. Therefore, in the M/V Hemingway’s case, it would be reasonable for our country to exercise complementary jurisdiction if the flag state and the state of the alleged offender’s nationality did not exercise criminal jurisdiction.Third, marine pollution accidents occurring in the high seas (EEZ of South Korea) should apply the relevant provisions of UNCLOS Part 12 regardless of the cause. The coastal state can institute proceedings when there are cases of marine pollution occurring in territorial seas or EEZ of the state and occurring outside of its EEZ but causing or being likely to cause damages to the state. For the lawsuit regarding the pollution accidents that occurred outside of national territories shall be suspended if the flag state institute proceedings on the same allegation within six months of the commencement of the lawsuit, and when the flag state ends the lawsuit, the suspended lawsuit is also automatically terminated. South Korea is eligible to file a lawsuit on the M/V Hemingway’s case, and because the flag state did not file a suit within six months, the judgement of the South Korean Court is considered to be valid. Fourth, while the Marine Environment Management Act of South Korea prescribes its jurisdiction based on the flag state of the violated vessel and location of the spills, UNCLOS prescribes coastal state’s jurisdiction based on the severity of pollution damage and compliance on procedures. Therefore, some supplements on related laws need to be made.

There has been a growing interest in recent years in the assessment of suitable vial/stopper combinations for storage and shipment of frozen drug products. Considering that the glass transition temperature (Tg) of butyl rubber stoppers used in container closure systems (CCSs) is between -55 °C to -65 °C, a storage or shipment temperature of a frozen product below the Tg of the rubber stopper may require special attention because below the Tg the rubber becomes more plastic like and loses its elastic (sealing) characteristics. Thus, they risk not maintaining container closure integrity (CCI). Given that the rubber regains its elastic properties and reseals after rewarming to ambient temperature, leaks during frozen temperature storage and transportation are transient and the CCI methods used at room temperature conditions are unable to confirm CCI in the frozen state. Hence, several experimental methods have been developed in recent years in order to evaluate CCI at low temperatures. Finite element (FE) simulations were applied in order to investigate the sealing behaviour of rubber stoppers for the drug product CCS under frozen storage conditions. FE analysis can help in reducing the experimental design space and thus the number of measurements needed, as they can be used as an add-on to experimental testing. Several scenarios have been simulated including the effect of thermal history, rubber type, storage time, worst-case CCS geometric tolerances, and capping pressure. The results of these calculations have been validated with experimental data derived from laboratory experiments (CCI at low temperatures), and a concept for tightness has been developed. It has been concluded that FE simulations have the potential to become a powerful predictive tool toward a better understanding of the influence of cold storage on the rubber sealing properties (and hence on CCI) when dealing with frozen drug products.LAY ABSTRACT: The growing interest in the assessment of suitable vial/stopper combinations for storage and shipment of frozen drug products has led to the development of a number of experimental methods to evaluate container closure integrity at low temperatures. The application of finite element simulations could aid in the investigation of the sealing behaviour of rubber stoppers for drug product container closure systems under frozen storage conditions by simplifying the experimental design space and the number of experimental measurements needed. In this work several scenarios have been simulated including the effect of thermal history, rubber type, storage time, worst-case container closure system geometric tolerances, and capping pressure. The results have been further validated with experimental data derived from laboratory experiments and a concept for tightness was developed. In conclusion, finite element simulations have shown the potential to become a powerful predictive tool toward a better understanding of the influence of cold storage on the rubber sealing properties (and hence on container closure integrity) when dealing with frozen drug products.

Ship collision damage assessment and validation with experiments and numerical simulations

A novel ship collision risk evaluation algorithm based on the maximum interval of two ship domains and the violation degree of two ship domains

Offshore platform structure has the ability to resist wave loading, wind loading, operation loading, and ship collision, therefore, it is important to investigate the structural behavior of platform taking into consideration soil-structure-pile interaction when the platform is subjected to ship impact at a different location on deck slab. The present study deals with platform supported by pile foundation. The effect of soil-pile interaction on behavior of platform to lateral impact load is investigated by using finite element simulation which is performed by ABAQUS software. From the results obtained, it is obvious that the ship collision position on platform will be reflected on ultimate capacity of structure so the structure will undergo to loose ultimate capacity due to damage that occurs from the ship collision. This study comprises investigation of pile lateral displacement, pile twist angle, pile shear force distribution, pile bending moment distribution and deck slab displacement. It also clarifies that the pile displacement has been reflected on pile critical length. The twist angle of the pile is more sensitive to soil type and loading condition. It is seems that the shear force distribution and bending moment distribution are affected by loading condition and soil type. Finally this study shows that the response of deck slab depends on soil type, soil-pile interaction and loading condition.

Estimation of leak area-pressure relationship for cracks on water pipes using models based on linear-elastic fracture mechanics

In the process of ship collision avoidance, the occurrence of human errors and its probability are stochastic and fuzzy. It is difficult to use the traditional Fault Tree Analysis method to carry out the quantitative analysis. To solve the problem, the fuzzy fault tree of ship collision from human errors was established by using fuzzy numbers to represent the occurrence probability of basic events and top event. And the grey relational analysis method was applied to the qualitative and quantitative analysis of fuzzy fault tree. The fuzzy significance set of the basic events was taken as a reference sequence, while the characteristic matrix made up of minimal cut sets was taken as a comparative sequence. The failure mode of human factor which may greatly influence the occurrence of ship collision was obtained by calculating the relational degrees between the fault mode of human factor represented by the minimal cut set and ship collision accident, which provides a reference for decision making to reduce the impact of human errors on ship collision accident..

With the global warming and a large amount of sea ice melting, the available Arctic Sea Route has greatly enhanced the value of Arctic shipping. Ship operations under icebreaker assistance have become an essential way to facilitate the safe navigation of merchant vessels sailing through the Arctic Sea Route in ice-covered waters, but they can also put the crew and the ship in danger caused by a possible collision between the assisted ship and the icebreaker. In this paper, a dedicated Human and Organizational Factors (HoFs) model of ship collision accidents between an assisted ship and an icebreaker is developed and analyzed with the aim to identify and classify collision risk factors. First, a modified model of the Human Factors Analysis and Classification System (HFACS) for collision accidents between a ship and an icebreaker in ice-covered waters is proposed, which helps to analyze ship collision reports. Then, a Fault Tree Analysis (FTA) model is utilized to analyze the fundamental collision risk factors according to the statistical analysis of accident reports and expert judgments based on the HFACS-SIBCI model. Finally, qualitative analysis is carried out to analyze collision risk factors under icebreaker assistance, where Risk Control Options (RCOs) are formulated. An important guidance for the risk control of ship collisions during icebreaker assistance in ice-covered waters is provided for lawmakers and shipping companies.

Accident-resistant Type B packages are used to transport radioactive materials such as spent fuel and vitrified high level waste in all surface modes, in accordance with national and international regulations. As with other modes, a sea-goingconveyance (vessel) carrying radioactive material (RAM) may be involved in a collision accident. If the vessel is struck byanother commercial vessel with sufficient tonnage and velocity, the RAM package may be impacted by the penetrating bow ofthe striking ship. The impact on the RAM package by the bow is less damaging to the package than the regulatory 9 m droptest. This is because the velocity is always lower and the bow always less rigid than the essentially unyielding target requiredfor the drop test. Thus, the only remaining mechanism for gross damage to the package is crush loading. For the package to becrushed, forces must act on two opposing sides. In this paper, the bow of the impacting ship is assumed to be able to impartan infinite force to one side of the package. The opposing force is supplied by the hull of the struck ship on the side away fromthe collision. Resistance of this hull to penetration by the package determines the maximum magnitude of the crush force. Workdescribed in this paper is aimed at determining an upper bound for this force.

Collision risk assessment in real-time is of critical importance to prevent ship collision at sea. Therefore, this paper presents a real-time collision risk assessment method based on an improved Non-linear Velocity Obstacle (NL-VO) algorithm. The proposed method consists of two main modules: trajectory uncertainty module assumes that the increase in the radius of the circular restricted area is consistent with the Wiener process; collision risk assessment module utilizes the NL-VO algorithm combined with the dynamic circular restricted area to evaluate the potential collisions. Several encounter scenarios in a specific port channel are designed to demonstrate the feasibility of using this proposed method to assess ship collision risk in real-time. The results are visualized and illustrated that this improved NL-VO algorithm can timely identify a ship that is in danger of colliding with the own ship and know when the collision will occur, which contributes to reducing ship collision occurrence probability.

Elastic behavior of ring-on-foundation

Inland waterway ship collision is a typical high-risk maritime accident which caused by many factors. In order to clarify the causal factors of collision of inland watercraft, the risk of inland river collision is analyzed. First of all, 419 ship collision accidents in the Yangtze River inland waterway from 2013 to 2017 are selected as the ext mining corpus. The human factors, ship factors, natural environment factors and management factors in the corpus database, will be applied as the target base. R language and text mining method is utilized to get a high dimensional and sparse original feature vector space set, which contains the features and the weight of the features. The chi-squared statistic is used to reduce the dimensionality of the set and 33 dimension features set which representing the ship collision risk factors are generated. Finally, the word cloud package in R language is invoked to make the date visualization, which provide a theoretical basis for the pre-control of inland waterway ship collision.

Under the backdrop of the robust growth of the global economy, the water transport industry is experiencing rapid development, resulting in an increase in ship collisions and a critical water traffic safety situation. This study uses text mining techniques to gather a corpus of data. The corpus includes human factors, ship factors, natural environmental factors, and management factors, which are used as target data to obtain a high-dimensional sparse original feature vector space set comprising eigenvalues and eigenvalue weight attributes. Chi-square statistics are utilised to reduce dimensionality, resulting in a final set of 33-dimensional text feature items that determine the causal factors of ship collision risk. Taking the four steps involved in the collision process as the primary focus, a Bayesian network structure for ship collision risk is constructed based on the “human-ship-environment-management” system. By incorporating existing ship collision accident/danger reports, conditional probability tables are computed for each node in the Bayesian network structure, enabling the modelling of ship collision risk. The model is validated through an example, revealing that, under relevant conditions, the probability of collision exceeds 90 %. This finding demonstrates the validity of the model and allows one to deduce the primary cause of ship collision accidents.