Topic Review
Wave Energy Marine Buoys
The power supply is usually the bottleneck for marine distributed systems such as buoys. Wave energy technologies are especially useful in this sense, as they can capture and convert the promising “native” renewable energy in the ocean (i.e., wave energy) into electricity.
  • 139
  • 08 Jul 2022
Topic Review
Vortex-Induced Motions of Floating Offshore Wind Turbine Structures
The ‘Green Shift’ from fossil energy (coal, oil and natural gas) to renewable energy (sunlight, wind, waves and tide) is now a global trend. DNV forecasts that by 2050, the installed floating global wind capacity will have grown from today’s 100 megawatts (MW) to over 264 gigawatts (GW), so that 2% of the world’s electricity demand can be supplied by cost-efficient and dependable floating offshore wind. Floating offshore wind is considered to be a viable solution at water depths exceeding 50 to 60 m with abundant wind resources. As a fast-evolving technology, it has the potential for less foundation material, shortened installation cycle and decommissioning, and additional wind power generation.
  • 64
  • 11 Aug 2022
Topic Review
Underwater Sensing Technologies and Applications
Currently, a variety of sensing methods based on optics, acoustics, and electromagnetics are widely applied for ocean observation and exploration. Acoustic sensing contains various sonar devices for seafloor mapping, submersible navigation, and underwater object. Optical sensing technologies applied to ocean exploration include underwater imaging for objects inspection, spectrophotometry, and fluorophotometry for environmental parameters monitoring. Technologies of electromagnetics are used for underwater metal detection such as mines and mineral resources, and for underwater inspections of cables and pipelines.
  • 309
  • 13 Dec 2021
Topic Review
Underwater Image Enhancement and Underwater Biological Detection
For aquaculture resource evaluation and ecological environment monitoring, the automatic detection and identification of marine organisms is critical; however, due to the low quality of underwater images and the characteristics of underwater biological detection, the lack of abundant features can impede traditional hand-designed feature extraction approaches or CNN-based object detection algorithms, particularly in complex underwater environments.
  • 24
  • 05 Sep 2022
Topic Review
Shipping Decarbonization
Decarbonization in the shipping industry could be achieved through technical and operational strategies such as Energy Saving Devices (ESDs) to reduce the fuel consumption of new and existing ships. According to the makers, ESDs can optimize fuel efficiency by up to 15%. Researchers review the current literature on stern hydrodynamic ESDs, which are mainly used on typical merchant vessels, i.e., bulkers, tankers, and carriers. 
  • 156
  • 05 May 2022
Topic Review
Scour Protections Design Optimization
The offshore wind is the sector of marine renewable energy with the highest commercial development at present. The margin to optimise offshore wind foundations is considerable, thus attracting both the scientific and the industrial community. Due to the complexity of the marine environment, the foundation of an offshore wind turbine represents a considerable portion of the overall investment. An important part of the foundation’s costs relates to the scour protections, which prevent scour effects that can lead the structure to reach the ultimate and service limit states. Presently, the advances in scour protections design and its optimisation for marine envi-ronments face many challenges, and the latest findings are often bounded by stakeholder’s strict confidential policies.
  • 328
  • 23 Mar 2021
Topic Review
Reconfigurable Vectorial Thrusters
The reconfigurable vectorial thruster (RVT) is a propulsion element that changes not only the intensity of the thrust vector but also its direction. This vector reorientation by a servomotor, for example, is usually faster than the intensity change. Thus, the possibility of fast vehicle reconfiguration allows the optimized choice of the reconfigured propulsion architecture according to different tasks, minimizing the trajectory tracking error and energy consumption. Moreover, the use of RVTs can significantly reduce the total number of needed thrusters in a vehicle.
  • 414
  • 19 Mar 2021
Topic Review
Performance of Unmanned Vehicles for Offshore Wind Turbines
Operations and maintenance of Offshore Wind Turbines (OWTs) are challenging, with manual operators constantly exposed to hazardous environments. Due to the high task complexity associated with the OWT, the transition to unmanned solutions remains stagnant. Efforts toward unmanned operations have been observed using Unmanned Aerial Vehicles (UAVs) and Unmanned Underwater Vehicles (UUVs) but are limited mostly to visual inspections only. Collaboration strategies between unmanned vehicles have introduced several opportunities that would enable unmanned operations for the OWT maintenance and repair activities. 
  • 99
  • 01 Jul 2022
Topic Review
Ocean Wave Power Generation Systems
According to the theory of mechanical vibration, only when the wave power generation system resonates with the ocean wave can the energy of the ocean wave be converted into electric energy to the greatest extent. Several topics are discussed: the current situation of ocean wave power generation system tests in real ocean waves; the optimization design of linear generator for converting ocean wave energy into electrical energy; some optimization control methods to improve the operational efficiency of ocean wave power generation systems; and the current policy and financial support of ocean wave power generation in some countries. 
  • 116
  • 04 Jan 2022
Topic Review
Marine Gas Engine
The interest in natural gas engines as an alternative to diesel engines has intensified as crude oil prices have risen and global environmental regulations have become more stringent. Natural gas engines can improve thermal efficiency through lean combustion, owing to combustion of a wide range of fuels; meanwhile, the low carbon content of the fuel reduces CO2 emissions, which is crucial in reducing greenhouse gas emissions. Natural gas engines also exhibit excellent fuel economy and low fuel costs. Unlike crude oil, natural gas is widely distributed worldwide and offers an advantage in terms of supply and demand. As a result, the demand for gas engines is increasing rapidly. Therefore, many marine engine manufacturers have developed micropilot-type gas engines that inject diesel fuel only for ignition.
  • 290
  • 25 May 2021
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