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_ Crew transfer vessels (CTVs) play important roles in the operation and maintenance of facilities under offshore wind conditions. When engineers are needed to transfer to offshore wind facilities for various maintenance operations on site, in most cases, the captain of the CTV pushes the vessel bow against the offshore wind tower using propulsion to ensure easy and safe transfer. In such operations, differential motion from the normal wave-induced dynamics can occur because of discontinuous static/dynamic friction at fenders. The unexpectedly complex dynamics occurring in the transfer can have a severe impact on availability. Given these motivations, both model experiments and numerical calculations were conducted to investigate the complex dynamics. This study clarifies the effect of the friction coefficient at fenders and the bollard pushing force on the stick/slip phenomenon.
- Europe (0.46)
- North America > Canada (0.28)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- Well Drilling > Drilling Operations (0.68)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Platform design (0.34)
- Facilities Design, Construction and Operation > Facilities and Construction Project Management > Offshore projects planning and execution (0.34)
Analysis of Sea Ice Hazard Factors and Influence on Seaport Operations in the Bohai Sea
Liu, Xueqin (National Marine Environmental Monitoring Center, Ministry of Ecology and Environment of the People’s Republic of China) | Zhang, Yujin (National Marine Environmental Monitoring Center, Ministry of Ecology and Environment of the People’s Republic of China) | Yu, Danzhu (National Marine Environmental Monitoring Center, Ministry of Ecology and Environment of the People’s Republic of China) | Yuan, Shuai (National Marine Environmental Monitoring Center, Ministry of Ecology and Environment of the People’s Republic of China) | Shi, Wenqi (National Marine Environmental Monitoring Center, Ministry of Ecology and Environment of the People’s Republic of China) | Chen, Zhenhua (The Ohio State University, Columbus)
_ Floating ice is one of the potential hazards that threatens the safety of seaport operations in winter. In this study, the monitoring data of the ice conditions around the Port of Yingkou in the ice zone of China were analyzed. The results showed a significant negative correlation between changes in cargo throughput and the magnitude level of sea ice. When the ice thickness is more than 15 cm, it can have serious impacts on port operations unless tugboats and icebreakers are deployed to remove sea ice from the channel. Introduction Ports play an important role in a nation’s economic system. Seaports are important nodes of the transportation network and gateways for domestic and global trade. According to data released by the Ministry of Transport of the People’s Republic of China in 2021 (Ministry of Transport of the PRC, 2021), 7 of China’s top 20 seaports in terms of throughput are located in seasonally frozen seas and need to cope with the impact of sea ice in winter. About one-fifth of China’s continental coastline is in seasonally icy seas. The Bohai Sea in northern China is a seasonal ice-covered sea with the lowest latitude in the northern hemisphere. Sea ice hazards are considered to be among the most serious natural disasters in northern China (Eicken and Mahoney, 2015; Liu et al., 2016; Xu et al., 2019) because they can affect human activities on the coast and the safe operation of projects. Sea ice can damage coastal engineering buildings and offshore facilities, crush and damage ships, and block ports and waterways (Yuan et al., 2015; Liu et al., 2019). Preventing sea ice hazards in coastal engineering has always been a focus of attention in northern China. The ice period in the Bohai Sea usually lasts three to four months during the winter season and has a certain impact on port operations in the ice area almost every winter.
- Transportation > Marine (1.00)
- Energy > Oil & Gas > Upstream (0.48)
- Government > Regional Government > Asia Government > China Government (0.46)
- North America > United States > Colorado > Ice Field (0.89)
- North America > United States > Alaska > Arctic Ocean (0.89)
_ Kawasaki Heavy Industries, Ltd. has developed, designed, and built a liquefied hydrogen (LH2) carrier (LH2C) in collaboration with Shell and ClassNK for a pilot hydrogen energy supply chain project conducted by HySTRA (CO2-free Hydrogen Energy Supply-Chain Technology Research Association) and promoted by the New Energy and Industrial Technology Development Organization in Japan. This pilot LH2C, the Suiso Frontier, debuted in 2021 to demonstrate a series of operational stages ranging from the initial cooling down/loading/unloading of LH2 to sea-going operations using a newly built pilot LH2 terminal in Kobe, Japan. The first international sea-going voyage by the Suiso Frontier between Japan and Australia was accomplished at the start of 2022. This study intends to describe briefly the ship design focusing on an overview of safety design and risk assessment results, and to provide an update on the demonstration progress describing the operational phase conducted as a series of demonstration tests highlighting the extended gas trial program conducted in Japan and the data-gathering exercise for the Suiso Frontier. Introduction In response to recent increasing demand for hydrogen supply in Japan (Takaoka et al., 2017; Agency for Natural Resources and Energy, Japan, 2014; Ministry of Economy, Trade and Industry, Japan, 2014, 2016), Kawasaki Heavy Industries, Ltd. (KHI) established a pilot CO2-free hydrogen energy supply chain (HESC) project to demonstrate the technology necessary to produce, store, utilize, and transport liquefied hydrogen (LH2) from Australia to Japan. As depicted in Fig. 1, the gasification of brown coal mined in the Australian state of Victoria will split fuel into its components, including carbon dioxide, which will be captured and stored securely offshore underground. This blue hydrogen will be liquefied and stored at 253°C (20K) in on-site tanks designed by KHI and transported to Japan using LH2 carriers (LH2Cs), also designed and built by KHI (Yamashita et al., 2014; RINA, 2017).
- Transportation > Marine (1.00)
- Energy > Renewable > Hydrogen (1.00)
- Energy > Oil & Gas (1.00)
- Transportation > Freight & Logistics Services > Shipping > Tanker (0.46)
_ A cooperative multicrane lifting operation with two vessels is often selected to lift a heavy suspended load. As the mechanics in cooperative multicrane lifting with two vessels are more complex than a single operation with a vessel, a thorough understanding of the coupled dynamical mechanics is needed. Unfortunately, there are few research activities regarding the fundamental mechanics and the motion analysis in multicrane lifting operations with two vessels. Given these motivations, both experiments and calculations were conducted to investigate the dynamics during a multicrane lifting operation with two different displacement vessels, and the impact of the distance between the two vessels on the coupled dynamics is clarified. Introduction Crane lifting operations in the ocean are crucial for constructing offshore structures and installing subsea facilities on the seafloor. The safety and availability of lifting operations must be analysed when planning construction. Wave-induced coupled dynamics between a vessel and a suspended load must be predicted for these analyses, as the coupled dynamics can result in more complex mechanics than just the dynamics of a floating structure. A cooperative multicrane lifting operation with two vessels is often selected to lift the heavy suspended load (van Winsen and van Dijk, 2019). The mechanics of cooperative multicrane lifting with two vessels are more complex than those of a single crane operation with a vessel. In such situations, the connection of the two vessels to the suspended load means that all actions taken on one vessel influence not only the motions of the suspended load but also the other vessel. Therefore, as a dynamic positioning (DP) system between these two vessels needs to be designed to optimally consider such characteristic mechanics for safety position keeping, a thorough understanding of the coupled dynamical mechanics is required when using cooperative multicrane lifting with two vessels.
_ Ocean current should be carefully defined during analysis and design of any deep-water system. This study focuses on introducing and testing a proposed simplified method—namely, a weighted current profile (WCP)—in filtering current profiles from a large database so the response analysis of a deep-water system can be carried out more efficiently. The method is tested for the operation of a deep-water work class remotely operated vehicle (ROV), connected to the surface vessel through an umbilical line, under more than 10,000 current profiles. The study reveals that the WCP method can successfully eliminate thousands of unnecessary current profiles from a big database. Introduction Ocean current is one of the important aspects that is essential to consider when designing any deep-water system. Because of the scarcity of measured current speeds and directions along the water column in the past, a vertical current profile was commonly assumed to follow one of the simplified profiles that can be conservative for deep-water systems. In the last decades, several measurements have been conducted on different deep-water locations, producing different current databases that can be used to define a more precise multidirectional current profile for designing and executing a deep-water operation. However, each database usually consists of thousands of fine current profiles that are cumbersome to analyze through conventional methods because of their large computational time. Performing statistical analysis on the deepwater current database is also still prohibitive without sacrificing the coherence of current speed and direction between depths along the water column.
- North America > United States (1.00)
- Europe (0.68)
- Energy (1.00)
- Electrical Industrial Apparatus (0.99)
_ The TurkStream offshore pipeline has been one of the most challenging projects in the offshore oil and gas industry in the last decade. It is a major gas-transmission system that is pivotal to the transport of natural gas from the large Siberian reservoirs to the Turkish and European markets. The system consists of two subsea pipeline strings of more than 900 km each that cross the Black Sea through water depths of up to 2,200 m. Its large outer diameter of 32 inches makes it possible to transport a massive amount—31.5 billion cubic metres—of natural gas per year from the Russian to the Turkish shore. A very thick wall of 39 mm is needed to ensure structural integrity. The sheer size of the system and the conditions in which it operates come with many challenges. Several are discussed in this paper, which focuses on the work carried out between 2010 and 2019, before the pipeline commenced operations. Available technologies had to be advanced to the next level on many fronts to ensure the success of this project. Introduction The TurkStream Offshore Pipeline is a major gas-transmission system that is currently in operation and comprises two pipeline strings in up to 2,200 m deep water. It connects large gas reservoirs in Russia to the Turkish gas-transportation network via the Black Sea, as shown in Fig. 1. The system currently has an annual capacity to transport 31.5 billion cubic metres (bcm) of natural gas over approximately 940 km. The line pipe is longitudinally welded with a nominal outer diameter (D) of 813.0 mm (i.e., 32 inches) and a wall thickness (t) of 39.0 mm. The material grade is DNV SAWL 450 with supplementary requirements F, D, U, and (light) S, according to DNV-OS-F101 (Det Norske Veritas (DNV), 2010), plus project specifications.
- Europe > Netherlands (0.28)
- North America > United States (0.28)
- Europe > Russia (0.24)
- Asia > Russia (0.24)
- Geology > Mineral (0.68)
- Geology > Geological Subdiscipline > Geomechanics (0.46)
Oscillations During Iceberg Towing
Korshunov, Vladimir A. (St. Petersburg State Marine Technical University (SMTU), St. Petersburg) | Mudrik, Roman S. (St. Petersburg State Marine Technical University (SMTU), St. Petersburg) | Ponomarev, Dmitry A. (St. Petersburg State Marine Technical University (SMTU), St. Petersburg) | Rodionov, Alexander A. (St. Petersburg State Marine Technical University (SMTU), St. Petersburg) | Nikushchenko, Dmitriy V. (St. Petersburg State Marine Technical University (SMTU), St. Petersburg) | Kornishin, Konstantin A. (Arctic Research Centre) | Efimov, Yaroslav O. (Arctic Research Centre) | Chernov, Alexey V. (Arctic and Antarctic Research Institute (AARI), St. Petersburg) | Svistunov, Ivan A. (Arctic and Antarctic Research Institute (AARI), St. Petersburg)
Abstract This paper describes a mathematical model of iceberg towing that considers an iceberg’s shape in an explicit form. The developed model allows for the analysis of oscillations appearing in towing systems in both stationary and dynamic modes. The proposed numerical model can be used to assess the nonlinear dynamics of the “vessel-rope-iceberg” system. An understanding of the peak values in the tow force should help to increase iceberg towing efficiency and ensure the safety of operations as a result of reduced iceberg roll and rope slide-off. Introduction To ensure the safety of marine operations in iceberg waters, a complex ice management system must be implemented in exploration or production activity. The physical impacting of drifting icebergs is one of the main ways to prevent their collision with fixed or floating offshore facilities (Efimov and Kornishin, 2016; Pashali et al., 2018). Perhaps the most effective technology to change an iceberg’s drift trajectory is to deflect it with the help of a tug vessel equipped with a special towing system. However, this operation can be complicated by a number of technical challenges associated with the dynamics of icebergs and towing system interaction. Despite the significant amount of iceberg towing experience accumulated in offshore projects off Canada’s east coast and west Greenland, there has been very limited research devoted to understanding iceberg dynamics during towing operations. Works by McKenna et al. (2003), C-CORE (2004), and Rudkin et al. (2005) investigated the relationship between iceberg stability and towing parameters such as the tow force, rope attachment point, vessel’s acceleration, and tow speed. Some more recently published works focused on the theoretical study of the iceberg towing process (Yulmetov et al., 2016; Yulmetov and Løset, 2017; Efimov et al., 2019). These works describe numerical models based on the analytical dependency of mechanics, and they reveal significant difficulties in the modeling of iceberg towing and the importance of nonlinear dynamic effects in the “vessel-rope-iceberg” system.
- Europe > Russia (0.47)
- North America > Canada > Newfoundland and Labrador (0.28)
- Europe > Russia > Barents Sea > East Barents Sea Basin > Ledovoye Field (0.89)
- Asia > Russia > Kara Sea > West Siberian Basin > South Kara/Yamal Basin > Leningrad Field (0.89)
This paper reviews and discusses some important design and position-control parameters and issues of the deep seabed nodule collector-miners (mining vehicles) of a few consortia, including the subsystems that the international consortia had independently developed since the 1970s. It includes the Ocean Minerals Co. (OMCO)–Lockheed design and full-scale deployment and touchdown tests of its self-propelled, remotely controlled miner on the 16,000-ft-deep seabed. Furthermore, this paper shows a remarkable change made on the previously disturbed sediment track surface. That track was elevated or disturbed in 1978 by OMCO’s Archimedean-screw miner track blades. Over a 26-year period, the elevated surface became flat and no longer elevated. First, the paper revisits major technological activities from past research and development, design, and tests conducted by the four international ocean mining consortia in the 1970s and proposes baseline design parameters and issue guidance for the development of commercial manganese nodule mining systems from the deep seabed. OMCO already reported the two full-scale, deep-ocean tests and concurrent development of a commercial mining system and technology of automatic ship-pipe-buffer-link-control with a self-propelled, automatic track-keeping miner or mining vehicle. Introduction and Technical Issues In the early 1970s, while 300-ft (91-m) water depth was treated as “deep water,” the goal of the OMCO-Lockheed commercial mining system and technology development in 1974 was to develop an 18,000-ft deep-ocean technology in five years. To achieve this huge challenge, the team and management looked at two choices: (1) an incremental step-by-step technology improvement approach, eventually reaching 18,000 ft (5,487 m); (2) a direct approach, with risks, to develop an 18,000-ft deep-ocean technology.
- Europe (0.93)
- North America > United States (0.70)
- Asia (0.68)
Development of a Supplementary Outboard Side Thruster System for Dynamic Positioning Control of Autonomous Surface Vehicle
Kato, Tetsu (Tokyo University of Marine Science and Technology, Tokyo) | Kawamura, Yamato (Tokyo University of Marine Science and Technology, Tokyo) | Tahara, Junichiro (Tokyo University of Marine Science and Technology, Tokyo) | Baba, Shoichiro (Japan Agency for Marine-Earth Science and Technology) | Sanada, Yukihisa (Japan Atomic Energy Agency) | Fujii, Shun (Tokyo University of Marine Science and Technology, Tokyo)
We describe the development of a side thruster system that can maintain the heading direction of autonomous surface vehicles (ASVs). At present, the Japan Agency for Marine-Earth Science and Technology, Japan Atomic Energy Agency, and Tokyo University of Marine Science and Technology are jointly working on the investigation of radioactivity in mud deposited in estuaries in Fukushima Prefecture, Japan. The main objective is unmanned mud collection using the ASV. For mud collection, we developed a side thruster system and implemented it to the ASV. We developed a unified main and side thruster system for one-man operation of the ASV using a joystick. We confirmed the operation of the ASV with the joystick in field tests. Introduction Radioactive materials were released into the atmosphere during the Fukushima Dai-Ichi Nuclear Power Plant accident in 2011. Several years have passed since the accident, and mud with a high concentration of radioactive materials may be deposited at estuaries and ports in Fukushima Prefecture. Therefore, it is necessary to conduct a mud radiological survey. Hence, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan Atomic Energy Agency (JAEA), and Tokyo University of Marine Science and Technology are jointly working on unmanned mud collection using an autonomous surface vehicle (ASV). Autonomous ships used in oceans, such as ASVs, have been actively studied recently (Peng et al., 2017; Mousazadeh et al., 2018; Peeters et al., 2018; Park et al., 2018; Silva et al., 2018). Dynamic positioning system (DPS) control of the ASV is necessary during the mud collection to prevent the tipping over of the mud collector and kinking of the connecting wire between the ASV and the mud collector. However, the ASV is not equipped with side thrusters and has no means of controlling its heading. Therefore, we endeavored to solve this problem by developing and implementing a side thruster system. A microprocessor (Arduino) is used to control the thrusters by sending control signals to it via a graphical user interface (GUI) on a PC. It is possible to remotely control the side thrusters using Microsoft Remote Desktop between the PCs in the ASV and at the land station. The configuration of this side thruster system is described in the section on its development. We implemented this side thruster system in the ASV and conducted operation tests at a port in Sōma City, Fukushima Prefecture. This location is used as the robot’s experiment field (Kawamura et al., 2019). First, the results of the side thruster bollard test confirmed that the thrust force was obtained as designed. Next, we conducted a turn and parallel movement test of the ASV. As a result, we confirmed that this side thruster enables turning and parallel movement of the ASV. Furthermore, we implemented a mud collector and a winch on the ASV to perform the mud collection test. From the test results, we confirmed no kinking of the wire during the mud collection. Therefore, with this side thruster system, we can maintain the heading of the ASV and prevent kinking of the wire under relatively gentle wave and wind conditions.
- Energy > Oil & Gas > Upstream (0.71)
- Energy > Power Industry > Utilities > Nuclear (0.54)
- Government > Regional Government > Asia Government > Japan Government (0.45)
- Information Technology > Hardware (0.86)
- Information Technology > Artificial Intelligence > Robots (0.66)
- Information Technology > Graphics (0.54)
- Information Technology > Human Computer Interaction > Interfaces (0.54)
Under extreme met-ocean environmental loads, floating platforms may exhibit complex dynamic states. This paper provides a novel method to predict the extreme motions of a floating platform based on a deep learning algorithm that can provide some guidance for platform operators. The distribution disciplinarians of ocean environmental loads were analyzed by the fractal theory and statistical analysis methods. The extreme values of six-degree-of-freedom (6 DoF) motions were selected as the characteristic parameters of the output layer. A long-short-term memory network (LSTM) deep learning network was established between the ocean environmental loads and the extreme values of the 6 DoF response. The predicted results indicate that the present LSTM neural network method could provide higher accuracy, with root mean square errors of 0.0724 and 0.0326 for rolling and pitching values, respectively. Furthermore, the relationship between the ocean environmental loading characteristic parameters and the early-warning index of 6 DoF platform motions was established by using the convolutional neural deep learning network (CNN). The present prediction method based on CNN was accurate, which can provide guidance for platform operations and early warnings in daily operations. Introduction Under extreme met-ocean environmental loads, floating platforms may exhibit complex dynamic states, including strong nonlinear and nonstationary characteristics (Qu et al., 2013). For this reason, it is of practical significance to analyze and predict the motions and dynamic responses of semisubmersible platforms and to provide accurate early warning evaluations (Du et al., 2016). To date, many researchers have focused on the environmental loads from ocean waves and wind and the dynamic responses of marine structures. Physical-based methods that take into account meteorological parameters and physical laws have been widely applied to wave and wind forecasting problems. For example, it has been generally assumed that the generation of waves can be described as a function of meteorological parameters such as the fetch length and wind speed (Kazeminezhad et al., 2005). The most popular of such models are the Sverdruv Munk Bretschneider, or SMB (Bretschneider, 1970), Wilson (1965), Joint North Sea Wave Project, or JONSWAP (Hasselmann et al., 1973), and Donelan (1980) models. Although those empirically based models are fast and accurate, they can only be applied to a limited number of scenarios (Bishop, 1983; Kamranzad et al., 2011). However, in the last two decades, numerical models (e.g., Deo et al., 2001) have been employed to forecast wave and wind characteristics, which have been made possible by rapid developments in computing technology. M Wu et al. (2019) studied predictions of short-term wind and wave conditions for marine operations using a multi-step-ahead decomposition-ANFIS model, which accounts for the uncertainty brought about by the prediction horizon. These methods have proven useful in predicting environmental conditions for marine operations. Takbash et al. (2019) used an extreme value analysis method, with long-term satellite records (30 years) of global wind speeds and significant wave heights as input, to obtain extreme values of global wind speeds and wave heights, set to analyze the peaks that exceeded thresholds. In the process, the authors proved that the extreme value analysis method is limited to the initial distributions and averaged conditions.
- Asia > China (0.95)
- Europe > United Kingdom > North Sea (0.24)
- Europe > Norway > North Sea (0.24)
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