Ketut Buda Artana

Probability of Ship on Collision Courses Based on the New PAW Using MMG Model and AIS Data

This paper proposes an estimation method for ships on collision courses taking crash astern maneuvers based on a new potential area of water (PAW) for maneuvering. A crash astern maneuver is an emergency option a ship can take when exposed to the risk of a collision with other ships that have lost control. However, lateral forces and yaw moments exerted by the reversing propeller, as well as the uncertainty of the initial speed and initial yaw rate, will move the ship out of the intended stopping position landing it in a dangerous area. A new PAW for crash astern maneuvers is thus introduced. The PAW is developed based on a probability density function of the initial yaw rate. Distributions of the yaw rates and speeds are analyzed from automatic identification system (AIS) data in Madura Strait, and estimated paths of the maneuvers are simulated using a mathematical maneuvering group model.

Simulation-Based Estimation of Collision Risk During Ship Maneuvering in Two-Lane Canal Using Mathematical Maneuvering Group Model and Automatic Identification System Data

This paper proposes a simulation-based method to estimate collision risk for a ship operating in a two-lane canal. According to rule 9 of the Colreg-72 navigation rules, in a narrow canal, a vessel shall keep as near to the wall that lies on its starboard side. However, a busy harbor entered through a narrow canal still presents impact hazards. Certain conditions in a two-lane canal, such as a head-on situation in the straight part of the canal during an overtaking maneuver and large curvature of a turning maneuver in the bend part of the canal, could lead to accidents. In the first condition, the ship alters its own course to the port side to overtake another ship in the same lane but the course altered is too large and hits the wall of the canal. In the second condition, the target ship may take an excessively large turn on the bend part of the canal, causing collision with the ship on the opposite lane. Collision risk is represented as the risk of damage to the ship structure and includes the probability of impact accident and severity of structural damage. Predictions of collision probabilities in a two-lane canal have been developed based on a simulation of ship maneuvering using a mathematical maneuvering group (MMG) model and automatic identification system (AIS) data. First, the propeller revolution and rudder angle of the subject ship are simulated to determine safe trajectories in both parts of the canal. Second, impact accidents are simulated for both conditions. The ship’s speed, and current and wind velocity are randomly simulated based on the distribution of the AIS and environment data for the research area. The structural consequences of the impact accident are measured as collision energy losses, based on the external dynamics of ship collision. The research area of the two-lane canal is located at the Madura Strait between the Java and Madura islands in East Java of Indonesia, as shown by the red line in Figure 1. A project for developing a new port and dredging a new two-lane canal to facilitate an increase in the number of ship calls is currently underway in the research area. Figure 1 shows the ships’ trajectories plotted using the AIS data as on January 1, 2011. The trajectories are mostly seen to be coming out of the canal, confirming that it is shallow and needs to be dredged.Copyright

Risk Assessment on Subsea Gas Pipelines Located at Water Basin of Jetty Area due to Dredging and Operation After Dredging

This study addresses risk assessment of 14″ gas pipelines buried closed to jetty area due to the plan to dredge the water basin at jetty area. The dredging plan is aimed to enable a more spacious maneuvering basin at the jetty area to enable larger vessel to be served and easier control of tug boat operation during berthing process. Before dredging, the gas pipeline is located 133 m from the slope. This condition provides enough protection to the gas pipeline since large vessel will not reach the pipeline due to vessel’s draft restriction. After dredging, however, gas pipeline will be located only 49 m away from the slope. The water area after dredging allows larger vessel will be in the vicinity of the pipeline and hence impose risk to the existence of the gas pipeline. Risk to the pipelines due to dredging activities (drop/drag anchor, drop clamshell/object, ship sinking, and ground instability) and due to various vessels operation after dredging (drop/drag anchor, ship sinking, and ship grounding) are assessed by implementing quantitative risk assessment. Hence, this study is focused on the assessment of risk to the 14″ gas pipeline due to dredging activity including risk assessment during operation of the jetty after dredging. Based on pipeline and environmental data, all possible hazards are identified. Some hazards are screened out using ‘Failure Modes and Effects Analysis’ (FMEA) to obtain the list of potential hazards. In order to evaluate the acceptance criteria of all potential risks, the risk profiles are composed according to DNV-RP-F107 “Risk Assessment of Pipeline Protection”. As part of the assessment, geotechnical assessments of submarine landslide due to dredging are also considered. The effective stress approach is implemented to the assessment and submarine slope stability is analyzed using Bishop’s and Janbu’s methods of analysis. The risk profiles for all potential hazards are reported, and simulation results for different slope ratios are given to illustrate the stability of slope configuration during dredging.© 2013 ASME

Observation Study the Walking Speed and Distribution of Ship’s Passengers as Basis for Passenger Evacuation Simulation

Several marine accidents was occured in Indonesia. Passenger evacuation is considerd as the last defence, which is used for eliminating the consequences of marine accidents. According to the convention of Safety of Life at Sea (SOLAS), the passenger evacuation simulation shall be conducted for reviewing the evacuation route on ships. The pasenger evacuation time is limited 60 minutes for roro passenger ships and for passenger ship having three main vertical zone is limited less than 80 minutes. It is hipotesed that the walking speed and passenger distribution is not represented the character of all nation in the world. Therefore, this research focus on the observation walking speed and distribution in ferry, in order to ensure that whether the guideline (M.Sc. 1238) could be represented in the condition in Indonesia’s vessels or not. The results of research show that the diferences result of passenger evacuation simulation between Indonesia’s and guideline’s walking speed is much closed. On the contrary, the distribution of passenger on the ship in the guideline could not represent the real condition in Indonesia.

Analytical Hierarchy Process (AHP) for Selecting and Designing a Mini LNG Plant: A Case Study of Batam Indonesia

Increase in demand for clean energy is one of the strategic issues in Indonesia nowadays, considering the significant economic growth of the country. A conventional LNG supply chain is not the best solution taking into consideration its high investment. The possibility of using a small scale LNG supply chain concept (Mini LNG) is recently sought by the government and private sectors in Indonesia. It is even more promising when we consider the amounts and number of stranded gas fields in the country. One of the main obstacles to the development plan is the geographical position of Indonesia as an archipelagic country.This paper presents a case study of LNG supply chain model of 10 mmscfd Gas Sales Agreement (GSA) in Batam and its design of LNG transportation model from Batam to Siantan-West Kalimantan [1]. The distance between Batam and Siantan is approximately 392 nautical miles. Two main objectives are covered in this paper. The first one is an implementation of the Analytical Hierarchy Process (AHP) to select the best location for mini LNG plant, and the second one is to design the LNG supply chain model based on optimization approach.The AHP model uses a pairwise comparison of 4 (four) qualitative attributes and 14 (fourteen) sub-attributes. 3 alternatives of location for mini LNG plant are evaluated, namely: Tanjung Uncang, Pemping Island and Janda Berhias Island. A sensitivity analysis by varying the weight of some critical attributes is also conducted to ensure that preferred location is sensitively selected with minimum error.The optimization of the LNG supply chain model is carried out by means of Gradually Reduced Gradient (GRG) methods. The Objective is to attain one design that will minimize investment (cost). Decision variables of the model are LNG plant capacity, storage tank capacity in loading and receiving terminal, vessel size, number of round trip, number of operating vessels, regasification capacity at the receiving terminal, and others.Copyright

Multiple Criteria Decision Making (MCDM) Process in Selecting Location for Floating Storage and Regasification Unit (FSRU): A Case Study of Bali Island Project

This paper presents a case study in selecting the best location for a Floating Storage and Regasification Unit (FSRU) in Bali. FSRU is an alternative to replace a conventional shore LNG terminal. The selection involves several criteria/attributes that can be grouped into two general attributes, namely qualitative and quantitative attribute. Multiple Criteria Decision Making (MCDM) approach is utilized to solve the selection problem, considering the capability of this method in solving multi-criteria problem with mutual conflict. Qualitative criteria is evaluated using AHP method to calculate weight of each criteria, and decision matrix algorithm is then utilized to convert preference of stakeholders into, consecutively, probability assignment, total probability assignment and preference degree. Quantitative criteria are also converted into preference degree and after combining with the preference degree of qualitative attribute, entropy method is then used to rank the alternatives. Selected location would be the alternative having the highest entropy. Four alternatives are under consideration; Benoa, Celukan Bawang, Pemaron and Gilimanuk. This research found that Celukan Bawang is the best location for the FSRU.Copyright

Risk Based Multi-Objective Simulation of Ship Main Engine Systems

The research is to understand the behavior of components and systems under various operational conditions, and with various maintenance policies. Therefore, this research is expected to give policy options to management. And further, inform the likely impacts of those options. This research presents a flexible system to simulate the effect of these factors to a system its reliability, operation and the maintenance costs. The model studied consists of failure rate, time to maintain, decision to maintain (or not), degree of how good the maintenance is done, the effect on component after maintenance, the maintenance cost, and the operation cost. A case study of main engine system with its support systems is presented using previous works data. Dynamic risk is presented in this work. It makes it possible to figure more frequently updated risk; therefore, it is easier for the management to modify or to mitigate the possible risk. The simulation shows predictive results for a given scenario of system configuration, operation and maintenance decision in simulating dynamic risk. In addition, this paper is addressed to provide a user friendly tool to simulate the system risk under some designed decisions both operation condition and maintenance policy. The result of a better understanding of system behavior and the risk depend on operation and maintenance policy is expected.Copyright

The Use of Computer Simulation in Developing Procedures for Marine Hazard Countermeasures

IMO (International Maritime Organization) has so far been producing several conventions with objective to ensure safety of ship operation and pollution prevention. In practice, however, implementations are rather exigent since some countries that ratified the conventions face so many difficulties due to mainly lack of fund and human resources. To solve this problem, efforts in educating people for marine hazard prevention and countermeasure must be supported by giving chances to people to get experiences directly in marine hazard prevention and countermeasure through performing simulation using computer. This can be made possible by setting marine accident or incident scenarios and participants involve in the simulation process will represent all parties related to marine Hazard countermeasures. This research is mainly aimed to develop and evaluate essential technological and engineering hardware and software for encountering marine hazard as well as essential risk management system, covered organizers and human resources, which have proper judgment ability and leadership. This research is also directed to seek optimum alternative method to train and educate people to get knowledge and experience on hazard prevention. The simulation is provided with a database system which eases the participant in performing their tasks. Responses to each scenario will be optimized by comparing three (3) indicators, namely: cost, resources and time for task completion. At the end of the simulation, a formal procedure for the countermeasure can be designed which guarantee those three indicators are minimum. A data mining system is also attached to the simulation to enable the database system automatically classifies the data according to the responses of the participants.© 2006 ASME